At least a couple times in my career I was given assignments that scraped the slimy bottom of the assignment barrel.
I'm not talking about the crappy assignments you get when you're a junior. Those assignments are part of paying your dues. I'm talking about assignments you get because no one else can do them or because everyone else has already rejected them.
About a decade ago I was given the task of preparing a bunch of videos and a few printed pieces for a client who was retiring. It was, I thought, a lose-lose proposition. If I did a good job, so what. A good party video. If I did a crap job, my ass was in a sling.
This is where personal integrity and a long view comes in.
You get these assignments, you do the best fucking job you can.
1. It's your job to come through.
2. The people you come through for, if they're not complete fuckfaces, will eventually come through with something better. They have memories. If they don't, then it's time to leave.
There's no such thing as an assignment that's wasted.
You always have a chance to impress someone.