When you choose to do an analysis on a store that you patronize it seems like an obvious choice because you think you'll have a good base of knowledge to start off with. This background knowledge can be a help and hindrance. It's difficult to accept there may be some favoritism at play and it's hard to cast a negative light in order to really evaluate the company. On the other hand it's much easier to understand the ins and outs of the business as well as build on your previous experiences and observations to find both strengths and weaknesses. Overall I think it's important to have had at least introduction with the company you're going to analyze, but it's even better to be as familiar as possible.