“Keep away from people who try to belittle your ambitions. Small people always do that, but the really great make you feel that you too, can become great.”
You may prefer to avoid arguments, but sometimes it is best to stand your ground. If you must fight, resolve to maintain control. Refuse to be childish, abusive or immature. You have legitimate feelings and are entitled to talk about them in a reasonable way. Keep a sense of humour, if possible!