Someone who is self-indulgent is sure to do the things that give them pleasure, make their life easy, etc., to the point where it's not a good thing, and perhaps over things that help others.

If I go to hurt my back a bit and take it easy for a day or two, I'm doing the right thing for myself. If I hire a maid to come in every day for a week, make everyone else come in and take care of me, while I sit like a queen on the couch, I have behaved in a rather self-indulgent way.

1. This may be a coy way of saying the person was fat, lazy, or both. 

2. A romance or science fiction novel might be considered by the author to be self-indulgent (I don't, but then, I like to read and would defend it), while reading about farming techniques would not be.