it doesnt.
a fun game is to total it up and try to determine how many mortgage payments that is and see how bad you can make yourself feel
I find myself trying to justify the amount by reasoning that I have been using Steam for 9 years, I don't own any other platforms than the PC and I don't really have any other vices...
Still stings though considering the size of my backlog and the reality there are some games I'll never play through to completion. Any game I buy these days are typically games I intend to play through.
This sale I've only bought four games which feels good: DuckTales, Castle of Illusion, Spelunky and Guocamelee