Age Appropriate?

I hate how our culture segregates by age.  I hate it.  I don’t understand it.  It’s counter-intuitive.  It’s self-destructive.  And yet it’s soooo pervasive.

As soon as you’re old enough to go to school (well, pre-school these days), you’re divided up by age.  You’re constantly associating only with those who are your age.  Well, and adults.  That can’t be avoided – otherwise I assume we’d even avoid that.  People more than a year or two apart from you in age might as well be aliens from another planet.  If you don’t have younger & older siblings, you’re plumb out of luck.

This of course continues well beyond school.  Once people are used to being only with others of their same age group, they seem at a loss to deal with anyone more than a few years outside of it.  Having had the opportunity (been forced?) to work with people both much older and much younger than myself, I don’t seem to have as many hang ups as others do. 

Am I the only one who finds this segregation thing to be rather bizarrely unnatural?  Other cultures seem to maintain a healthy appreciation for inter-generational interactions.  I wonder why it’s so problematic in the US (at least in my admittedly limited frame of reference!).