Once when Theo Epstein was being grilled by a couple of us hard-hitting and smart reporters about a variety of topics, he interrupted the whole thing to offer a thought that rings true today.
"You're going to have surprises."
He said plenty more that day, some of it way more colorfully than that. Boiled down, his point seemed to be twofold:
1. Sometimes the more you know, the more you realize all that you don't know.
2. Stuff happens.
We've been reminded of that wisdom virtually every day of a season that hasn't played out the way we thought it would.
If the season ended today, the Braves, Phillies, Pirates and Brewers would make the playoffs while last season's three National League division winners -- Cubs, Dodgers, Nationals -- would not.
How did we get here? Actually, that's the easy part. If we'd known then what we know now…
Let's check out 10 things that have surprised us:
1. Braves' offense
Atlanta was tied for 10th in the NL in runs last season. The Braves are first in 2018, averaging almost a run per game more. Raise your hand if you saw this coming. Sure, that's partly because of the kids -- Ronald Acuna Jr. and Ozzie Albies -- but it's also veterans Nick Markakis and Freddie Freeman having great years. In addition, infielder Ryan Flaherty and outfielder Preston Tucker have been smart acquisitions by general manager Alex Anthopoulos.

2.Aaron Judge, RF, Yankees
How would Judge follow up a season in which he led the American League in homers, runs, walks and strikeouts? Surely, there would be some regression as opposing scouting reports exposed the weaknesses in his swing. That has not happened. Judge's on-base percentage is up. His batting average is way up. He's on a pace for more walks (and strikeouts) and slightly fewer home runs. Judge just celebrated his 26th birthday, and he is showing that he's going to do things in this game others simply can't do.

3. D-backs' bullpen
This has been the best bullpen in the Majors thanks to a couple of tweaks by GM Mike Hazen in adding setup man Yoshihisa Hirano and closer Brad Boxberger. Also, there's the continued emergence of Archie Bradley as one of baseball's best relievers. The thing is, Arizona had the NL's second-lowest bullpen ERA last season at 3.78. This season, the D-backs have lowered that by more than a run to 2.52. 

4. Gerrit Cole, RHP, Astros
Having watched Justin Verlander get even better and Charlie Morton get dramatically better, we probably should not have been surprised by Cole's improvement in his first season after being acquired by Houston from Pittsburgh in the offseason. His repertoire has changed some, and his strikeouts are way up and baserunners way down. This seems to be the case of a really smart and really talented player taking advantage of the Astros' deep reservoir of data to take advantage of his own strengths and to exploit the weaknesses of opposing hitters. At this point, Verlander, Cole and Morton might finish one-two-three in AL Cy Young Award voting.

5. Angels' rotation
We just knew that one of these seasons the Halos would be able to keep enough of those talented arms healthy to create a first-rate rotation. So far, so good. Garrett Richards, Tyler Skaggs, Andrew Heaney and Nick Tropeano have all done exactly what the Angels hoped they would do, and rookie Shohei Ohtani has been every bit as good as advertised.

6. Josh Hader, RP, Brewers
Hader dropped his changeup to throw more sliders, but he's still about as basic as they come, throwing a 94-mph fastball more than 70 percent of the time. With a whip-like delivery, the ball is hard to pick up and has some wicked movement. The result has been video game-like numbers: 56 strikeouts in 27 1/3 innings and a 0.51 WHIP (seven hits, seven walks). Milwaukee is back in the middle of the playoff race for a lot of reasons, including arguably baseball's most unhittable reliever.

7. Aaron Nola, RHP, Phillies
Nola has emerged as a true ace in his fourth season with Philadelphia. He's throwing fewer fastballs and curves and more changeups to give opposing hitters a different look. Beyond the Xs and Os, we're probably simply watching the final emergence of a 24-year-old who was projected to do just that from the moment the Phils used the seventh pick of the 2014 Draft on him.

8. Pirates' offense
We were so focused on the trade of franchise icon Andrew McCutchen that it was easy to overlook how much talent Pittsburgh still had. That has shown up in an offense that has gone from 13th (4.1 runs per game) to third (4.89 per game). Colin Moran and Corey Dickerson have been terrific additions, and Starling Marte is having his best season. Catcher Francisco Cervelli is one of the most underrated players in the game.

9. Mookie Betts, RF, Red Sox
Betts finished second in AL MVP Award voting in 2016, sixth in '17. He's a two-time All-Star and two-time Gold Glove winner. So how does Betts qualify as a surprise? How much better can a very good player get? Turns out, lots. He has taken pretty much every part of his game to a new level. Betts is leading the AL in an assortment of offensive departments, and if the season ended today, he'd probably win the AL MVP Award.

10. Trevor Bauer, RHP, Indians
For most of Bauer's career, he has been that wild stallion, immensely talented who had been unable to fully harness all his gifts. He appears to have taken that final step this season and emerged as one of baseball's most dominant starters after adding a slider to his arsenal that seems to have made all his other stuff better.