How Do You Know?

...Simple, its just a feeling you get when you know or when you think you know.
1) If a person does not want to talk to you (no interest)
Q: How have you been?
A: Ok lar / fine / not bad / ect...
Q: What have you been up to lately?
A: School lo / Nothing much / ect...
Q: Have you seen ... / Have you heard about... / Have you been...
A: Nope / Yes / ect...
Q: Do you know ...
A: Really? / ect...
Q: (just told a joke - lame/funny/insulting/criticizing...)
A: lol / ahahaha / ... / ect...
Q: (asked a question)
A: (no reply)

Well, basically the reply will have no signs of wanting to continue the conversation or something like that...

2) Forgot something (pkf)
Well, you'll most probably be wondering every now and then that there was something that was needed to be done

3) You're unsure of how you feel
Procrastination

4) You're in deep shit
Well there are many reason for this... for example, forgetting to do your assignment/homework/research and tomorrow is the deadline XD or you pissed someone off whom you care and whatnot