I have to say, I disagree with you there =(
My sort of 'life goal' at the moment is to learn/try as many different things/skills (and hopefully get good at them). I do this mostly just cause I find it fun to learn new things, like new languages.
But also, you never know when it might be useful in life. Sometime I may find myself in some foreign country, a few words of their language can help. And for jobs - I bet I can earn more by doing several things at once (btw the 3 things that interest me most is art, writing and sciences - in sciences I include computer stuff like programming)
But mostly I do it just for fun =). I mean, my life would be very booooring if I only focused on 1 thing. There are simply thousands of things to see, do, learn, experience in the wide world - and I would be very sad if I don't do them all by the time I die =(
Not saying I can do it all, but it's a dream...