The most important social events in our lives (the ones we look forward to most; save our best clothes for) slowly alter with each decade we grow older. Proof:

Childhood: Birthday parties (daytime)

Teens: Birthday parties (nighttime)

20s: Outings at various clubs/bars

30s: Dinners (generally dates with prospective partners, which will eventually whittle down to one partner, who will morph into spouse)

40s: Dinners (generally with spouse and other couples to discuss children's education, house renovations etc)

50s +: Church