You don’t need to be a push-over, simply be kind. A very wise friend of mine told me wonderful advice once. No matter who you encounter – kind or evil, be the person you know you are and stay true to yourself, do not change yourself for the person that they are.
This same wise friend had a very difficult upbringing, and a rather abusive mother who is now elderly and ailing, relying on the mercy of kindness from others. His sisters harbor bitter feelings and are fine if she is mistreated, but my friend feels otherwise as he has learned to break the cycle and forgive – mind you, not forget, but forgive so that he can move and live the life he choses to live, not the life that is the result of actions of another.
This is all much easier said than done, but this can be applied even in the most brief and simple encounters with a passer-by.