I have worked for two different owners, and the culture really depends on them. Overall, the interpersonal relationships that develop depend on the individual. In my case, I was very lucky to work with an amazing owner, and great coworkers who would be willing to assist and be flexible with shift and personal life.
The downsides to this is that there is little to no room for growth, unless you are considering become a franchisee. And there are no benefits.
The upsides, if you display that you are an employee worth holding onto, your coworkers and manger/supervisors will be more willing to assist in any flexibility within reason.
Great team, dependable hours
No room for growth, no benefits