I just wish I wouldn't get upset

I can remember sitting in French class and , as I saw it, failing my French test, thinking; "I just wish I wouldn't get so upset about things why do I always get so upset?".
Somehow I decided that to get upset was one of the worst things I could do. Don't know where I got that from, no incident special, probably just life itself. But I've carried that one around for years.
Every once in a while I think I have room to get cranky or speak up, and it doesn't turn out as I think it should, and wham, I'm back to suppressing, giving up and giving in.
As far as I can tell, that's not really life, that's my conforming to a set pattern of how I've been taught to be, not being itself.
I was once told; "It's not what you say, it's who you are being, that has you be heard or not".
Sounds good but I can see I made that one more opportunity to suppress myself even more, cause obviously if you are being the right way, you will get heard, right?
Mark Joyner from Simpleology says what we need to do in this climate is get stronger. But what does getting stronger look like? More stubborn? More fierce?
Personally, I just wish I wouldn't get upset. I wish I could view all circumstances as opportunities, and joyfully embrace each one. Yeah, not quite there yet. :)