Pros
Independence (you really run your own ship), lots of social contact for an outgoing person, variety of products and preparation techniques (make coffee, smoothies in a blender, microwave meals, cook chicken or pizza in a regular oven, just hand out cookies, crackers, candy, etc.), variety of tasks and people means that the job doesn't tend to get old, great job for people-watching!
Cons
Some foods take too long to cook, some customers are rude or expect you to have product available continuously, unpredictable schedule (from 1 to 6 days/week) which means unpredictable pay, sales plans don't always work (such as insufficient product), and late breaking changes in sales plans (and they don't pay me enough to have a Smart Phone to check email during the day)