Exclusivity and mistreatment is always unpleasant, there is just no denying it. Sometimes we have to live with it and sometimes we may even choose to ignore it for our own purposes. But if you are being excluded based on who you are or a legally protected characteristic, then discrimination is a basis for legal action.
There are a number of local, state, and federal laws that mandate equal treatment in various settings, and these outline the obligations of businesses or institutions dealing with the public. But not all situations, even when discriminatory, are necessarily going to make a great basis for a lawsuit. Let's look at some places where discrimination might occur and what situations are more likely to be worth fighting for.