I definitely agree. Due to past circumstances, I think my 'friend threshold' is deeply buried, but once you pass it I think it's hard to express how much I actually care about my friends. They'll always be on my mind, I'll always be caring about them, expending mental energy on them, be ready to do anything for them at the drop of a hat.
When you have that much 'give a damn' about someone, you really do have to be picky about your friends, a) you'll never have enough energy to live and b) if you aren't picky, you'll eat yourself alive with bad feelings when those kinds of things aren't appreciated/abused. As 'mean' as it sounds to say 'we only have so much room in our hearts,' I think its definitely true, but once you get a slot there the 'love' is infinite. :)