When I was in sixth form, I taught my friend how to create empty files using Python. He soon learnt that you could get around the quota enforcer this way.

He was curious to see what would happen if you filled the entire drive to maximum so he ran the code for an ~8TB file. Before he could delete it, he was told to log off. Nobody could save their work and backups weren't performed for 24 hours.

It's safe to say they weren't impressed when they found this.