How one tune can change..

it's really amazing how one tune can change so quickly...at first i thought that my chemistry teacher was very strict and all that...but now after him teaching us for few days, i found out that he can be strict but not strict with us too. he could also joke with us and have fun together.but sometimes i think that his emotions vary a lot and he could be one minutes really happy and next minute really serious and sadly, this reminds me of a mental hospital patient....-_- no offence to anybody...seriously, now that he seems that he can be a nice person, i guess having lessons which these teachers can be fun as well....providing we do our homework of course...^O^....i am really lucky to have all the good teacher this year..=^.^=...unlike some other friends of mine who had gotten a particular monkey as their teacher....seriously no offence directed at anyone!