Well, when I was at Download '06, I was talking to the guitarist of one of my favourite bands (SikTh, RIP) and he asked what my name was and I said "VIOLET....but people call me Lettuce." and he said "oh, you called Violet because of the hair?" and I was like "eh?" forgetting I had a bright purple noggin, then he was like "OH....do you have purple hair because your name's Violet?" I still didn't get it!
Lettuce is a highschool nickname that stuck XD