Sometimes, my dear helen, you just have to realize that people are going to open this way, understand what they mean even if the way they say it doesn't match what you feel should be the "proper" way and say something really witty, like, "Go ahead, that's what I'm here for." For a follow up lesson, listen to yourself and see if you say things that may be similarly creatively misinterpreted by the pedantic nitpicker (not that *I would know what *that would be) and follow the Golden Rule, doing unto others etc.