I once spent several months working in a very bare bones operation that was still being built/expanded as it was being populated with workers. As a result, our building's bathroom facilities hadn't been hooked up to a sewer as yet and we had to use Port-O-Johnnies (yeah - in 120F degree heat

) Whenever one of us had to run an errand to the main headquarters building, we would make a point of using their bathroom, as indoor plumbing was considered quite the luxury. We had to travel in pairs for safety anyway, so usually it was "Who needs to use the potty?" and that's how we got a travel buddy...
Which led to me one day telling the very important, but quite personable Chief of Staff: "Oh, I just came over to take advantage of your plumbing!"

I practically ran away from him as soon as the words escaped my mouth! Ugh... although the alternative meaning to the literal never seemed to cross his mind and he was a bit confused as to why I made such a hasty retreat...