I worked there for about a year a few years back. It is a cool and fun job. The pay is also not bad depending on foot traffic at the location you will be at.
You will have your daily A-holes who come in complaining about the service, or their phone not working and expect you to fix it. The worst is people threatening to cancel service because you can't give them what they want. Customers with no insurance and no upgrade available are the worst to deal with.
One thing to keep in mind is.... Whenever a girl comes in with phone issues and hands her phone over to you to look at, make sure you look through her pics. 9 out of 10 times you will find some interesting stuff.
Girls will also hit on you constantly just for a discount or free accessories.
Good luck bro.