Sure, it is possible, I could do it quite easily as I'm used to looking for the silver lining. But the real question is why do it? All emotions are important and have to be lived. If you don't feel jealousy, how can you know how the other person would feel if you'd cheat them for example. It might seem like a strange example but think about it, it's an emotion so strong, you can't rationalize or tell someone "they'd feel bad".
Or if you suppress grief, do as if nothing ever happened, are you actually surpassing the obstacle or is it simply a denial, which when it hits again, will hurt twice more.
Emotions shouldn't be fought with, you can suppress them to an extent, for example not to show them in public, which I find acceptable and polite, but 24/7 happy go lucky will simply drive you nuts. Not a healthy way to live.