I have that problem too as an American, now that I've started speaking with Brits more often. I have to be very careful around whom I say, for instance, "I'll just put my pants on."

(Okay, yes, I understand generally one would hope you're careful around anyone you would say that to, but in this instance I was wearing a rehearsal dress and had taken my jeans off underneath them, and was about to leave for a break and put my street clothes on again. And happened to say that next to the ONE English guy in the cast. Ay ay ay.)