At holiday gatherings, after you've updated your family and friends on everything going on in your life -- like how you won a free European vacation at a reverse raffle, went on a snorkeling expedition in the Mediterranean, saved a woman from a shark attack, proposed to her on the spot (she said yes!), and then were introduced to her parents, the Grand Duke and Duchess of Luxembourg -- you're going to need some other stuff to talk about.
You know, stuff that's more interesting and exciting.
Baseball would qualify. Because the sport is evolving all the time, even avid fans can benefit from brushing up on the latest trends and talking points, beyond the surface-level standings and Hot Stove stuff.
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Let's go over five of them here so that you are prepared to wow relatives (and royalty) with your wealth of baseball knowledge.
1. The shift might not really be that big a deal
After Joe Maddon's Rays popularized the shift early this decade, use of the defensive strategy has exploded, reaching nearly 32,000 instances in 2018, per Statcast™. That's an enormous jump from even just two years earlier, when the sport saw just fewer than 25,000 shifts in 2016. Because the rise of the shift has accompanied the slow death of the single (the number of which has fallen each of the past five years), there has been much discussion about whether MLB should shift away from the shift to help induce more action and more offense.
Alas, there's not a great deal of evidence that banning the shift -- perhaps by requiring that two infielders be positioned on each side of second base at all times and/or requiring all infielders have their spikes in the dirt while the pitch is being delivered -- would produce the intended effect.
The shift, defined by Statcast™ as having three or more infielders to one side of second base, was in effect for only 17.4 percent of plate appearances in 2018. As noted by Jayson Stark of The Athletic, the shift prevented 517 would-be hits in 2018. That's 517 hits spread out over 2,431 games -- or about three across the entire league on a given day. Most of them singles.
Despite the stark rise in the number of shifts, the league-wide batting average on balls in play has remained relatively static. At .296 in 2018, it was only one point lower than in 2010, despite a 1,308 percent increase in the number of shifts. As an MLB.com study found, the effects of the shift may not be as large as long assumed.

The issue at hand isn't fewer hits on balls in play; it's fewer balls in play, period. The percentage of swings resulting in a ball in play has fallen from 41.9 in 2010 to 37.4 last year.
2. That opener thing? It worked, and it's not going away
As anybody who was around in Europe in 1848 could tell you, not all revolutions are successful.
So when the Rays rewrote the baseball script by putting a "starter" after a reliever for the first time in a May 19, 2018, game against the Angels, there was no guarantee the bold new plan would take. But reliever Sergio Romo retired all three batters he faced in the first, "starter" Ryan Yarbrough followed with 6 1/3 effective innings, and "the opener," as it's come to be called, was off and running. The Rays wound up using it 55 times in all, and they had 23 additional games in which relievers accounted for all of the innings pitched (what has typically been referred to as a "bullpen day"). By year's end, the Twins and A's were trying the bullpen experiment, too, and the Brewers used a variation of it in the postseason.

Because the Brewers fell short of the World Series and the A's bullpen-oriented American League Wild Card Game plan didn't work out well, some fans might be dismissive of the opener idea. But in the larger sample that was the Rays' 90-win season, the opener was an unqualified success. The club's pitching staff ERA went from 4.43 prior to the adoption of the opener to 3.50 (second-best in the AL) the rest of the way, and their 3.61 ERA in the first inning was best in the AL. 
Little wonder that other teams are expected to try the opener in 2019. In addition to the Rays, Twins, A's and Brewers, the Rangers, Pirates, Giants, Tigers, Blue Jays, Padres and Marlins are among the clubs that have expressed openness to the idea in the new year.

3. Up is in
The 2018 season was the first in MLB history in which there were more strikeouts (41,207) than hits (41,018). This was, in a word, inevitable. A new league-wide strikeout record has been set every year since 2008.
One obvious, oft-cited reason for the uptick in strikeouts during the past decade is the increased prevalence of high-velocity arms. The fiery fastball is all the rage.
But in recent seasons, we've actually seen fewer fastballs overall. Pitchers are keeping hitters off-balance by more frequently employing breaking and offspeed stuff, and the fastball has taken up a decreasing percentage of total pitches in the four seasons of available Statcast™ data.
Percentage of fastballs
2015: 62.3
2016: 61.2
2017: 60.6
2018: 60.0
So pitchers are using fewer heaters. And in an era in which many hitters are actively trying to elevate the ball for power, the heat rises (just like you were taught in science class) when it is used. Not long ago, it was commonplace for pitching coaches to preach the value of executing low in the zone to induce grounders. But increasingly, pitchers are challenging hitters up in the zone with the fastball.
Percentage of fastballs thrown high in zone
2015: 16.0
2016: 16.2
2017: 18.7
2018: 19.0  
With more hitters revamping their swings to try to lift the ball (the average launch angle has increased in each year of Statcast™ data), the high fastball contributes to the increase in swing and miss.
4. Position players pitch, like, all the time
OK, not really all the time. But in the season in which Shohei Ohtani became MLB's first true two-way talent since Babe Ruth, Ohtani was far from the only dude doing double-duty.

There were a record 65 instances in which a position player pitched, not counting Ohtani's 10 starts. Per research from CBS Sports' Mike Axisa, there were more position-player pitching appearances just in the past four seasons (135) than in the 20-year span from 1990 to 2010 (120). So, we have every reason to suspect 2019 will bring us more of the same, with the unusual becoming increasingly, well, usual.
This is another extension of the bullpen revolution taking over baseball. Because relievers are taking up a higher percentage of innings year after year (that percentage was 40.1 in 2018, an all-time high), managers know better than to burn their relief arms in blowout games, because they're likely to need those arms the next night. So, they throw a position player to the wolves.
And the wolves eat it up, by the way. Batters posted an OPS north of 1.000 against the position players this year. 
5. If the win ain't dead, it's dying
Jacob deGrom's 10 wins in 2018 became a new low for a Cy Young starter. He appeared in first place on 29 of 30 ballots because, with so much better data both traditional (ERA) and modern (FIP, WAR, ERA+, etc.) available to them, the voters rightly recognized that deGrom's 10-9 record was probably the stat that told you the least about the unequivocal success that was deGrom's season.

But that exceptional example is far from the only reason the win is losing its luster as a worthwhile baseball metric. The fact of the matter, unfortunately, is that starting pitchers don't qualify for the win enough for it to really be much of a measuring stick anymore.
While random relievers can vulture wins by facing a single batter at an opportune time, starters have to go a five full innings to qualify. There were only 3,618 instances this season in which a starter went at least five innings. That's 24 fewer than in 1993, when the league had two fewer teams and 324 fewer games played!
As a result, the starters' win total for the year was 1,515 -- less not only than the total from three full seasons from the 28-team era (1993, 1996 and '97) but an additional seven full seasons from the 26-team era (1978, 1980, '83, '84, '85, '88 and '89). 
And here you thought your engagement story was crazy ...