Okay, so here's the info about overindulgence:
There's also a really great book (which I have and Chelsea, you can borrow if you'd like!) called How Much is Enough? by Jean Illsley Clarke, Connie Dawson, and David Bredehoft. I attended a workshop with Jean and David this fall, and know lots.
Basically, the summary of the whole thing is making sure your children or the children for which you care do not think they are the center of the universe -- helping them understand how much is enough stuff, attention, time, choices, etc. It's a great book, an easy read, and the website has tons of information. This research helps parents and caregivers feel okay about saying "no" to their children in a society that is swinging towards very permissive parenting.
What scares me is when I hear people say, "I just don't like saying "no" to children." Man, that's frightening.