It niggles

Of late, I have discovered that I have no good insult for someone who's being wilfully nasty or stupid on purpose or just generally getting in the way for no good reason. I'm looking for a word that's profane, but not too profane, like something you could use in front of your parents if they're just slightly understanding but which you would never dream of saying to your grandmother, and which is also (for preference) not in common usage.

Strangely, this really feels like something that I knew and used at one point but which I have forgotten in the past few weeks, which let me tell you is an extremely weird feeling, sort of like when you're wandering around the house wondering what it is you were about to do and trying to remember but really having NO IDEA if there even WAS anything or if you just think there was. Or like when you're packing to go away for the weekend, so anything you forget isn't too important, but you still feel like you forgot something and even if it's not important it's niggling at you. Niggling, I say.

Can anyone help me?