There's many worst parts really. I've got some really horrible roomates this year. One is completely tone deaf and insists in singing loudly in Spanish (his native language). He also doesn't ever sleep for extended periods, just takes "siestas" throughout the day, so often there's bad singing along with bad laptop speakers at 3 in the morning.
But right now, I think the worst part is that they've already turned the heat off for the rest of the semester (since we had all that nice 80º weather last week) and now it's been in the 30º's for the past 4 days. So our room has slowly cooled down to be in the mid 50's.
Nothing like having to wear a coat to sit at the computer. I'm sure Mollishka would sympathize.