Give Yourself Permission
Something bad happens. You feel sad. What's the first thing you start doing? If you're like me, you start stifling your natural feelings and trying to pretend it's not hurting.
My friend Casey gave me the best advice ever when he told me "Give yourself permission to be sad." He explained that you're using energy that could (and usually is) better spent on actually dealing with the situation.
Accept that you're angry when something makes you mad. Accept that you're hurting when something hurts you. And on the flip side, accept that you've got a crush when someone smiles at you and it makes your heart flutter, and be proud when you get recognition for doing something great.
You can't help how you feel. So feel it, instead of fighting it. Don't waste the energy. You'll need it for other things.