Pros
Great opportunity to interact with customers and get to know them on a personal level. You get to learn a lot about health and fitness. When company reps come in and give out free samples, that's pretty cool too.
Cons
Low volume store = lots of down time. And the Lying. A majority of what you do at this job is lie. "You need this vitapak" or "You should be taking (insert GNC brand product) along with what you're buying today". When you first start working there, you're eager to meet your goals and feel great when you up sell a customer on a product. Talking a customer into buying a second vitapak or fish oil with their purchase makes you feel like you've made a great sale, albeit at the expense of their wallet. After time, you get tired of hearing yourself give the same sales pitch that is a load of crap which most customers can see through, and also coercing people into spending money on a product they can buy for a lot cheaper online. Most of the time the item you recommend to the customer is only suggested because it either offers commission (which is where you truly make your money at GNC) or it meets a sales criteria you have to meet by week's end or else you run the risk of being spoken to by either the store manager or regional sales director and getting written up.