how could you get to know ?

In my case,I did switch numbers without thinking doubtly and was a cheeky boy could always get A-B grade. But now on the contrary I became so particular about little things. I don't know why i could be like that.

A reason comes later anyway, however i always try to know NOW. It's my bad habit. Even psychology, philosophy and mathematics as well, there is "a only way of thinking" that conforms to each field. That's why we can watch things from various angles and with various ways. That is interesting.
People can grasp meanings only through his mind. If our mind has a lot of drawers, we may be able to put a lot of things. I think.