Not to sound too selfish and mean, but having my own darkroom means not having to share with anyone else. Not having to share their chemical spills, not having to share the equipment they break, not having to share the mess they make, etc.... And on the flipside, if I make a mess of my darkroom, I can leave it messy without worrying that I'm bothering someone else. It's my very own space, and that means I can personalize it to suit my work the best.