Got mine when I was a framer.  Was my 2nd day on the job, we were really busy and skipped coffee.  It got around lunch and seemed like we were going to skip that too.  I was hungry so when I was grabbing some nails I nabbed an apple and put it in my tool belt.  I climbed back up on the roof and started eating it as I was waiting to get some more trusses.  Lead hand yelled, "Hey! what do you think you're doing?" I said, "having a snack", there was some underbreath cursing from his end followed by "It's NOT snack-time yet!" (I still finished the apple...)
Stuck ever since.  By day 3 nobody in any of the four crews, including the boss ever called me Tyler again.  Snack Time became my full name.  Usually just Snack.
I was surprised my boss never accidentally wrote it on any of my pay cheques.  A few of the lead hands even forgot my actual name after about a year.
Just picked an interesting way to spell it for my handle that nobody else seemed to be using.