So many of mine on here already (trout pouts, botox, 'haitch') but also:
People who wait until the cashier tells them how much their shopping is before getting their bag, getting purse out, deciding whether cash or card etc. And who take their time packing their grocery bags, holding those who are in a hurry up in the queue behind them.
Some phrases such as 'thinking outside the box' (just say, be original!) and 'at the end of the day' (ultimately!).
Teenagers telling me colour / symbols / metaphors etc in a piece of literature have no connotations or deeper meaning. (Just do your work for goodness sake!)
Adverts that are being shown on the tele
When a political leader lies on their CV - can you trust them?
