1. Even after graduating from college, they treat Sundays through Thursdays as “school nights,” which means they feel obligated to be super disciplined—to get enough sleep, to exercise, and to eat well and all that.

2. They generally reserve “fun” for weekends.

3. If you keep them up past their regular bedtime, there better be a good reason for it. Because they’ll get kind of anxious staying out past a certain hour unless it’s in the name of doing something worthwhile.

4. There are shockingly vast gaps in their pop culture knowledge since they weren’t allowed to watch more than half an hour of TV per night growing up and their “screen time” was always strictly limited. Expect to be wowed on occasion by their sincere confusion when you drop common references.

5. As an adult, they still feel a little guilty watching more than half an hour of television per night, or squandering too many hours surfing the Internet. Because they actually believe that too much time in front of screens will rot their brain.

6. And that if they don’t read enough, their vocabulary will shrink. (Don’t be surprised if you catch them revisiting the vocab flashcards they used to study for the SATs in a desperate attempt to offset the impact of a Netflix binge.)

7. They consider it incredibly rude to look at your phone during dinner. “No electronics at the table” is a rule they plan to enforce in their own household one day.

8. If you suggest watching television while eating, they’ll think you’re about as evolved as a caveman.

9. They won’t ever eat takeout from the disposable containers it arrives in—because food should be plated, and plastic forks and knives are absolutely unacceptable unless you’re picnicking.

10. They will always clear their plates after finishing a meal and offer to help do the dishes and/or clean up.

11. They will definitely be offended if you get up from the table before they’re finished eating.

12. They actually wait the full two minutes for the electric toothbrush to complete its painstakingly long vibration cycle.

13. They’re still afraid of disappointing mom and dad, so they call home at least once a week to indulge their parents’ questions and to give them a general update.

14. But they won’t answer an incoming call from either parent unless they’re able to devote their full attention to a minimum twenty minute long conversation. Picking up the phone and declaring “can’t talk” simply isn’t an option as they were raised to respect the people responsible for spawning them (and abruptness still equals potential grounding to them).

15. Being introduced to a significant other’s parents is a really big deal to them, but they won’t sweat the event since they tend to impress people in such situations with their politeness and genuine desire to please authority figures.

16. They keep insanely thorough To Do lists and derive sincere pleasure from crossing items off. It’s wise to beware of lingering To Dos, which can become the source of great anxiety.

17. Their apartments are crazy neat because they were required to keep their childhood bedroom museum tidy at all times. If there’s any disarray in your house, don’t be surprised if they start organizing on autopilot.

18. They make the bed automatically every single morning, within five minutes of waking up.

19. They need to go crazy sometimes—to break free from all of their self-imposed rules because they probably never went through a proper rebellious phase.

20. After they get a little naughty, however, they’ll punish themselves for it. A drunken evening out might be followed by several days of abstinence from alcohol, intense workouts, mindful eating, and daily meditation.

21. Their goody two-shoes habits will probably rub off on you a bit and as grateful as you are for the positive influence, it will always be your job to loosen them up.