No matter how hard I try, I can't stop myself from saying "Thanks a lot" to people when completing a transaction in a shop. This may sound trivial, but you have never heard me say it with my American/Dublin4 quasi-twang accent! It really sounds like I'm taking the piss! I'm aware of it to the point that I know I've done it right after I say it, but I can hardly go back and say "Excuse me, but you know the way I said 'Thanks a lot' just there? Well I really meant that you know, I wasn't being smart, you really did provide an excellent service!"
I have tried to modify it to a simple "Cheers!" but this evolved into a "Perfect!" which was just downright silly. I'm not one to say the old boring run of the mill "THANK YOU" but perhaps for simple peace of mind I should start trying it. It annoys me as much as it does when I hear people answer the phone with the word "Yellow" instead of "Hello"...what's THAT about???