Fuck It
1) Use this when you're giving up on shit. Like you really just don't wanna do it any more and BOOM. "Fuck It"

2) Also To be used when you need to psych yourself up for something! Another more vulgar version of Nike's "Just do it!" and "Why not?"
Man I don't know if I should jump of this cliff... Nah. Fuck It I'm going for it! *Jumps*