Well, thousands of people shared the small hills they're willing to die on. Here are some of the top and best comments:
1. "Red Delicious apples are trash apples. I'm gonna still recommend better apples. And judge you harshly when you stick with the Red Delicious."

2. "Tiny and jumbo paperclips should not be mixed. This happens at work, despite having dedicated containers for each. Worse, they often dump pulled staples in the mix too."

3. "Lightning McQueen totally won his race against Doc because Doc blatantly broke the rules as laid out by Sheriff."

4. "Edward Norton's character in Fight Club has no name. It is most definitely not Jack."

5. "Reese's Peanut Butter Trees should be called Treese's!"

6. "Toilet paper goes OVER not under."

7. "Women’s clothing should have more pockets."

8. "People need to either wear headphones/ear buds or mute their devices in public."

9. "Returning shopping carts to their spots at all costs. Cart Narcs!"

10. "A Reuben has CORNED BEEF and SAUERKRAUT. Not TURKEY and COLE SLAW. Stop calling it a 'turkey Reuben.' Just stop. Normal people call that a Rachel."

11. "Those giant yellow or white arrows painted on the ground at gas stations… Yeah, they’re there to maintain order. Stop coming in the wrong direction, cutting in front of people, and being an asshole."

12. "Parallel parking as a test to get your driver's license is idiotic when you will spend much, much more time on freeways going 60–100 mph and emergency braking."

13. "The Oxford comma. Use it."
14. "That 8 to 4 is better than 9 to 5."

15. "I’ve said it before and I’ll say it again: Wreck-It Ralph did not need a sequel."

16. "Zack Synder’s Watchmen is not a faithful adaptation of the source material. (And is terrible on its own terms.)"

17. "You can’t save a parking space unless you have a car with you. If you are standing in a parking space waiting for your spouse to drive there from around the block, I will block in the spot, cancel my plans, and wait there all day."

18. "People are too loose with the word 'impossible.' Being very difficult is not the same thing. And nobody has ever or will ever do an impossible thing."
19. And lastly: "Pineapple can go on pizza."

You can read the full thread of responses on Reddit.
Note: Some responses have been edited for length and/or clarity.