Wet matches.

I figured the possible reason why people face disappointment (and all other nasty feelings such as hurt and anger that comes with disappointment) in the first place is because of this thing that is, expectation(s).

You expect the bus to arrive on time so that we won't be late for an appointment, but it arrived later than you expected and you feel pissed off and wanna complain to the SBS.

You expect to be praised when you've done a good job in something, but what got thrown into your face is comments about you not having fulfilled something else, and then you feel shitty.

You expect everyday to be smooth sailing and life to be a bed of roses. And when you face any setbacks or failure, you become dejected and feel that the whole world is against you.

We expect an apology or some kind of acknowledgment to try to make up, but the other party doesn't even wanna look at you. So you count to sixty sets of ten, looking at him, hoping he'll turn and look back at you so that you can make the first move to say sorry instead of him. But he doesn't. So you are disappointed.

So, it's better not to have any expectations about anything at all.