I love collection stuff. Like Megaman X Collection, I barely touched any other game until I had my Sky Room filled. I love having all the hearts/energy tanks that games have to offer. Getting every weapon, every power, every useless scrapt of paper is what hitting the power button is all about.
But on the other hand collecting X amount of something so you can move on to another level just to collect X+10 amounts of something gets annoying after awhile, like Level three. Not only is it not fun to collect the same thing over and over again, it's usually not challenging either. "Hey look A Golden Whatchamabobber and look nine more behind it. Now that I've gotten those ten let's turn left and wowhee 10 more!"