Okay, this is utterly trivial. But here goes anyway.
If my MIL - who is lovely - ever encounters my DSs (who are 2 and 4) naked - running about after a bath, getting ready for bed, whatever - she always goes "Oooh, nudie rudie!" I've heard her say it about her DGDs too. She literally says it EVERY TIME she encounters an unclothed child.
I just hate it. I'm fairly relaxed about nakedness, and my DSs don't, yet, think that naked = rude. I'd like to preserve that for a wee bit longer. I can't seem to find a way to ask her not to say it to my DCs without sounding mean or disrespecful. So I'll just grumble on here...