Stress
Bad news first—the first thing you'll find every morning are giants stacks of shirts that need mending, pants that need hemming, and socks that need darning. Every time you finish one stack, a supervisor will stop by to drop off 200 more socks. And yes, you'll have to deal with a "these darn socks" pun every single time.
The good news is it's a fairly relaxed environment, all things considered. Some people even consider it to be one of the least-stressful jobs around. There are no publishing deadlines or events to worry about, and if you own your own store you can spend as much or as little time with each client as you feel like.
You may get Ms. Demandy Pants every now-and-then, but if they ever step out of line, you've got a whole bunch of needles and shears ready to go.
...clearly we're kidding, please don't attack anyone.