I am not middle-aged, but have felt differently since just before Christmas:

I've started running, working out everyday, and eating better...for no real reason at all.

I'm spending more money on stuff like a bigger lcd tv, new cell phones...stuff I really don't need, but GOTTA have.

I'm more conscious of how I dress and my appearance.

My wife has noticed that I seem to be more independent.

I enjoy going out more often, with or without friends

Any other male just feel differently, seemingly out of nowhere?