I'd say bad staff rather than just staff. Most of my staff are an absolute pleasure, but getting rid of bad apples sure is a PITA given the LRA. I really wish it was as simple as saying "hey, this isn't working. You don't want to be here / You're not performing up to standard / You're a round peg in a square hole. Let's do both of us a favour and ease you out of here so that you can find somewhere that's more suited to you."

But frankly, that's not the problem that bugs me most. My number one problem I dislike the most is getting debtors to pay on time. Again, many are a pleasure, but the one's that play up... oh boy! Not much fun.