"What a man is depends on his character; but what he does, and what
we think of what he does, depends on his circumstances. The characteristics that
ruin a man in one class made him eminent in another."
I think that Shaw is saying that opinions about people can change based on their environment and class. Something that is considered good in one society can be viewed as bad in another, just based on where those societies are. An example of a behavior that can be compared to this quote is "the idea of an aggressive real estate developer with an aggressive sanitation worker. Both are in business, but their qualities may be judged differently." This idea demonstrates that in an affluent area where the real estate is competitive and the hunt for housing is difficult, somebody would want that aggressive real estate developer. The customer can afford whatever the developer throws at them because they are wealthy, and the developer is trying to make good money as well. People are open to new ideas and new developments. However in a less affluent area, an aggressive developer can be a burden on people. If people love their surroundings, are against new housing projects, and can't even afford it, the aggressive developer would really bother the members of that society. This quote is just saying that the same person can be viewed different under different circumstances, and they can be positively deviant in one area, while negatively deviant in another.