I find such feelings are fleeting, and then the focus shifts to other things (case in point, UltraMarknus' post ). I'm kindof glad though, because if you don't have something to look forward to, I think you miss out on some of the joys of collecting!
I'm a picky collector, but there are a few things I feel a sense of completionist about and after I do, I feel a sense of satisfaction, but at the same time a sense of anger for spending the extra cash for stuff I would otherwise not want. For me, it's a love and hate thing; good thing this doesn't happen too often.