Lol the life lesson which is essential is who cares about what others want. As long as you are following their orders and the rules, you're fine. No need to please their imagination. Also don't fear people. They are humans like you with ears and a tongue. I would say don't expose your stutter if it doesn't bother your job that much. Quitting is easy. Anyone can quit. Successful people are those who pull thru. If you quit in this minor job, life ain't gonna be easy. This is coming from a person who worked from door security in retail. I would stop some scary looking people and ask for receipts. In return they would curse at me. But who cares what they think is the mentality you need.