My opinion on Indulgence vs Compulsion is;
Indulgence is a voluntary act while Compulsion is an involuntary act. Even though you would be doing the same thing with the same amount of that act, the difference between voluntary or involuntary is what defines Indulgence and Compulsion.
Such a hairline difference is what sets them apart from each other.
You may be able to have over-indulgence on something but if you can stop that act at any time then it isn't compulsive.
If you try to stop but you feel the urge and get to the point of acting out explosively after restraining, that is compulsion.
When something pleasurable becomes painful, a burden or unenjoyable and you can't control your ability to stop it, it is a compulsion.
Yeah, that is also what I was getting at.
My examples of Compulsion would be like those who are addicted to drugs, alcohol, or cigarettes. Even if they try to stop, they have this urge to obey their needs. Example of Indulgence is like going to a random picked strip club or maybe going to the movies. Compulsion is harmful, Indulgence is harmless (if it has nothing to do with compulsive inducing acts).