The word Shit is used in many different contexts. Observe:
1. When you recall something you haven't done, eg.
Geography homework; it's like "Oh shit!"
2. When you hurt yourself rather stupidly eg. *kicks brick* "Argh... shiiittt!"
3. Laughingly. When someone does something really retarded, eg. *watches friend dive into the
paddling pool* "Ahaha shit!"
4. When annoyed by something which is gross or wasting time, or quite literally, shit, eg. *dog has just crapped all over the floor* "Uh, shit!?"
5. When you are really, really
riled about something and there is no-one to blame or vent on. "ARGH
SHITTT!"
6. Said rather sarcastically or ironically, eg. *laughs with mates, saying "I probs got like 2% on that test!" thinking "yeah right!" and you get it back and you actually did* "Oh shite..."
Shit is crap. Crap is poo. Poo is excretion. Excretion is in the loo. The loo is dirty. Dirty is messy. Messy means to have a mess. Mess needs cleaning up. Cleaning is very shitty. Shitty is the act of being shit.
"Oh shit!", "
Oh shat!" and "Oh shite!" are all variants of explaining the
shitness of the situation.