I always say ''I'll be back in a minute.''
I don't mind when someone says they're off to the loo/toilet/bathroom, but I can't abide it when they very loudly announce ''I'M OFF FOR A WEE!'' Like they're expecting an Oscar for such a performance!
One woman I work with very loudly announces ''I NEED A POO!'' Then, when she gets back, she says ''You should have seen the size of it!'' And she'll say it during a break when we're eating!
That's why she's only a work colleague, not a friend!
I'm far from being a prude, and am quite open-minded, and don't object if someone says quietly ''I need a wee/pee'' but when they announce it proudly and loudly, it makes me cringe!