Are you speaking English to me?? No entiendo!

This evening I was at the Mexican supermarket, Ranch Market, about a 10 minute drive from my place in Phoenix. I saw they had guayaba drink, something I hadn't seen since my travels to Central America. So I got some. Having just ordered some pastries in Spanish and spoken back to in Spanish, I wandered over to the juice stand to continue to "practico mi Espanol". Again ordering in Spanish, and waiting to be spoken to in Spanish. The lady asked, "Large or medium?" I kept asking "como? como?" with confused looks from her. Duh. After about 2 minutes I looked at her and said "mediano". When your mind is ready for Spanish you stop hearing English words. And to have this happen near where I live. F-U-N-N-Y !!!