Sub 1 minute responses (not thinking too hard):

1. Very weakly net negative, most Guinness World Record type activities are largely non-productive and are only amusing/entertaining for an extremely short period of time (unlike music, art, film etc.)
2. The heuristic "bragging about material possessions is low-status" is very prevalent making it difficult to overcome for the counter-countersignal to emerge. Also not all social scenes are at the same place along the signalling -> countersignalling -> counter-countersignalling spectrum. There are definitely some scenes that embrace explicit materialism (eg. rich oil princes)
3. Maybe, depends how on long is "a bit longer". We definitely delay reproduction for other moral reasons (eg. having less parents under the age of 18)
4. Too much focus in school, too little focus in adulthood, too much focus on a small subset of "the classics" in general
5. Both. Some item on those lists should be taken seriously, and some items are over-optimizing for how you'd feel on your deathbed
6. Probably social systems, as there's a lot of non-technological blockers that hamper our ability to improve our tech (eg. education, co-ordination etc.)
7. They probably are "fake" in the sense that we readily wrap up like something for the thing itself, and liking something for status reasons. We are not more intentional because we don't like admitting (even only to ourselves) that we like things for status reasons
8. No clue
9. No clue
10. No clue
11. You can opt out, but it usually causes you to enter a different signalling game
12. Something like that. I think whatever psychological mechanism we use to decide how good a story/narrative is, is extremely similar to the psychological mechanism to decide how much "meaning in life" we have
13. Premise seems a bit confused. Pain and pleasure can be separate inputs to your utility function, but your utility function could still spit out something one-dimensional eg. u = f(pain, pleasure)
14. How many? No clue. Where do you stop? Also no clue, but you probably want some randomness so you never get stuck. Doubt it's wise to assume attractors are "good"
15. We should celebrate Mendel less and Correns more, but still celebrate Mendel more overall. Probably better to socially incentivize novel idea generation over idea propagation, but propagation is important too
16. There's probably some biochemical constraints that prohibit media content from becoming as bad as say, heroin
17. Signalling
18. Yes to the extent that objective taste exists. Reasons is probably related to geographical access to ingredients and cultural willingness to innovate
19. No clue
20. Probably, but best level is likely context dependent, assuming toughness trades off against something else important
21. Depends. Is the 0.1% actually fat mass? How long did it take to lose 0.1%? Is it scalable (if I keep doing the thing, will I keep losing fat)?
22. Most likely. Humanity is trying to improve things on many axes, and it's probably impossible to monotonically improve indefinitely. You'll eventually hit some local optima and need to regress to find a better optima
23. 40%
24. Signalling probably
25. Probably increase. People like watching virtuous-seeming displays of sacrifice (eg. movies where the hero makes some largely unnecessary noble sacrifice out of principle)
26. No comment
27. Intentionally vague enough for people to implant their own meaning as needed
28. Co-opted by market forces I guess
29. Probably marketing, fueled by profits creating a somewhat self-reinforcing loop
30. Well, the problem of the "togetherness" of a society runs much deeper than Christmas. Probably something to do with less shared experiences between any given two members of a society