For me the time friends realized I wasn't kidding was when we went (with some reluctance on my part) to an Indian restaurant (IIRC one near the Vanderbilt campus). The folks working the kitchen there... they tried, bless their hearts they tried, but it was quite clear that despite multiple attempts they really had no idea what was meant by "Not Spicy". Everyone else at the table is sampling the latest attempt to meet my request and going "WTF, this isn't spicy at all", and I keep repeating the pattern of taking one bite and thinking "wow, I think they actually got it this tiOH MY G-D THEY DIDN'T WAAUGH".