Oh boy, this is going back but here's the ones that stuck in my brain. Most are DS since by the time DD came along we were expecting this stuff. Some of our preschool fun -

- DS lifted his head to follow conversations day 1, we thought it was a fluke but he kept doing it from then on. (he wasn't 100% so there were some face-plants into collarbones or shoulders initially but if there was conversation - he seemed to want in) Even now (12) he will gravitate towards adult conversations whenever he can.
- we hardly baby-proofed anything - we would tell them that they couldn't touch something and explain why and they would listen even at 6 months old (we ended up having to do some babyproofing for visitors)
- we did have a doorknob thing on the door to the basement - DS figured out how to open it as soon as he was able to stand (he'd put his hand on the top and use his weight to push the top part down hard enough to turn the knob, we then wrapped the knob with a cloth under the plastic thing to make it harder, he figured that out instantly, pulled it out and repeat his move).
- DD declared that she wasn't going to wear diapers at 19 months old and I think she might have had 2 accidents, ever
- both kids' daycare made a few comments (can't remember the details)
- the recommended ages on games, toys and puzzles never seemed to match when our kids would find them interesting
- we walked into a room at a local museum that had some planets as decorations hanging in random order around the room from the ceiling and DS promptly pointed out that one was missing, we assumed he was talking about Pluto not being there (some of our books were dated) and he said - I know but they are missing Neptune and sure enough he was right.
- at 4 he got really, really mad at a dinosaur zoo exhibit where the parasaurolophus didn't make the right sound (he knew ALL about them and pretty much every other dinosaur)
- the dentist made some comment about brushing your teeth to get rid of the sugar bugs, DS rolled his eyes and said it isn't the bacteria, it is the waste from the bacteria that causes tooth decay (I have to assume he learned that from some tv show???) The dentist looked at me a little weird.
- the games he would try to get other kids to play with him at the park usually got some laughs

I'll also add that while all of that was going on he was in therapy for speech delay so it was an odd mix at times. In contrast, DD had an insane vocabulary (or maybe our expectations were just warped).

Definitely agree that all kids are different.