(To) Hype up means to feel overly confident in yourself for a brief moment and lose control through being overly happy and having an adrenaline rush.
Mostly in cases you get hyped up to music and dance and sing or your friends making you feel like a bad bitch and you can't control your happiness.
A term coined by "CoffeeMc'Coffee" that means: When a false promise is made and it is not properly fulfilled - it subverts expectations by delivering a lower-quality result instead of what was originally promised.
Person A: YO LISTEN! I GOT THE BEST COOKIES IN TOWN! COME ON OVER RIGHT NOW!!
Person B: Oh cool, let's go there.
Person B: Dude.. what the heck? You're giving me cookie dough? YOU GOT ME HYPED UP FOR COOKIE DOUGH??