When you don’t get your way, be cheerful about it. There’s no good reason to be any other way.
Being angry, spiteful, resentful, despondent, destroys your effectiveness and repels other people. That’s not going to accomplish anything good.
You can’t change the past by being angry about it. What you can do is dramatically improve the present and the future by being cheerful.
Be cheerful and you do better work, attract positive people, improve your relationships and interactions. Be cheerful, and see opportunities that you’d otherwise never notice.
Be cheerful, and escape being sizzled by stress and paralyzed by anxiety. Be cheerful, and reap all the benefits of truly enjoying the moment you’re in.
Yes, by all means be realistic. At the same time, be cheerful, and position yourself to make the very best of reality.