And actively seeking "challenge, danger, conflict and conquest" - well, two of those (challenge and conquest) are good things to seek, but the other two (danger and conflict) are stupid and destructive.

Not to play apologist, but I'd say that people's intuitions for danger and conflict are far too broken to justify blanket acceptance or rejection of actions carrying those emotional tags. Playing chicken with a 300-pound Sumatran tiger is a dangerous act tagged correctly, granted, but ancestral instincts don't often do that a good job of carrying over: people's intuitions for social, technological, or habitual dangers are often completely out of whack relative to their actual importance, and habituation might well be indicated in many cases. Conflict being more of a social construction, I can't make blanket statements about it as easily, but I strongly suspect similar considerations would apply.

I agree with the rest of your comment.