One of the hardest things to learn, it seems, is how not to give an excuse for one’s decisions.
Mandalay’s wording is good. And it is sufficient.
“Excuses, excuses” is an apt title for this post, but a better one should be, “No excuse necessary.”
You aren’t required to give a justification. And don’t let yourself be bullied into making one up. Hell, if your friend absolutely will not let the conversation drop, you simply say, “I’m sorry, as you recall I have been to these in the past. They are just not my cup of tea. i hope you enjoy yourself, though.”