Picky Prissy, My Pet,
We all have food aversions (for me, it’s the banana!) so I understand where you’re coming from. Additionally, you are not required to clean your plate if it’s a dish you don’t fancy. That said, here is my advice next time you find yourself in this situation: Try and muster the strength to try the dish, you might like it! In the event you can’t even entertain the idea of tasting said broccoli casserole, no need to announce it (*compliments only when others have graciously taken the time to cook for you!), simply leave it on your plate and try not to call attention to your aversion. Also, if the meal at someone’s home is buffet-style and the host has prepared a dish you don’t care for, out of respect, take a tiny portion on your plate however don’t feel obligated to consume it.