Here are a couple examples:
“They were such a tight crowd, I had to fall back on the solid bits and didn’t get to work on new jokes”
This just makes you stronger in those jokes. Yes, it's one step closer to their expiration date, but you're always going to be cycling in the new and washing out the old.
Even if you didn't add a new tag or find a slight word adjustment to make them better, you’re making your “fallback” stuff stronger… and think about that! You have fallbacks that are good!
“They were so rowdy, I only did half the jokes I wanted to and spent the rest of the time doing crowd work.”
This is part of the job and it’s an important skill you’ll need to use for the rest of your career. You get better every time you do it. And it’s not only helpful for bad crowds. These are skills you can use to help with segues, emceeing, and even reading a good crowd.