Are there developmental stages to dating?

I find guys in their mid-to-late twenties completely inscrutable. Completely. Their behavior as it pertains to dating makes no sense to me, whether they’re dating me, actively not dating me, dating my friends, actively not dating my friends, pursuing my friends and taking them on one date and then never calling again, obsessed with girls who are completely nuts, etc.

This has never been an issue in the past (I am 24 now, and the bizarro dudes in question range from 23 to 31). Additionally, dudes well into their 30s seem to behave in a normal, predictable, sensible manner.

Am I inferring a pattern where none exists, or do guys tend to go through stages of dating wherein they do seemingly nonsensical things in their 20s and eventually return to normal? Is there some kind of internal conflict or existential crisis driving this behavior that I’m just not aware of? Does anyone, especially dudes who have been through their 20s, have any insight?