Space has definitely become my biggest issue, and no matter how hard I try I can't seem to get ahead of it.
I too blame scarcity sometimes. There were a few books that I screwed myself over on by waiting (like, 10 yrs ago) and my knee-jerk reaction was to pre-order *everything*, even if my interest was minimal. Cuz, ya know, just in case. I kept that up for way too long, and to this day I fight that urge every time I scroll through solicits!