Can or Can't....?

Today i was having a quality time with 2 of my besties and we're landing on Starbucks, a nice-to-have place for gossiping :P
In the middle of our conversation, a question came up in my mind...

w: guys, do u think that someone can change his own nature behaviour?
c : hm...i think so, actually it depends on he himself.
y : in my opinion, he can't change it totally but at least, he can diminish it, if he wants it to.
w: errr...okay! but it's such a hard thing to do, isn't it? sometimes i think it can't be changed although u want it badly.
c : it can be! believe me..my dad was a stubborn person. (fyi, her dad is one of the nicest guy ever, very caring and loving person to his fam, esp to his wife...so sweet...)
w: i give u an example, for some cases i am a short-term-memory kind of person esp. for something outside my business (if someone asks me for a help, for instance). I really don't want that happened but it happens out of my control. my bad, dunno y.... :'(
Another example, how about a temperament character? is it possible to change and remove it??? i know it's really really a hard job, but can't it? it's one of the characteristic i hate much!!!
e : maximized your reminder! hahahaha :p j/k
well, i think it's a bit harder to change the 2nd one. but u can always have it!
y : well, 1st example, u absolutely can change it. U just have to struggle with that and have an eager to learn. Big effort is needed!
2nd example, maybe u can change it but it's a bit harder than the 1st one. so the possibility is less than the 1st.
e : but still, u can, if u said so!! the choice is yours =)
w: um..okay! *still wondering*

At the end, we came to a conclusion..."it is easier for u to change some bad characteristics, for which u can have other ways (incl. ur big longing) to keep it away slowly but sure. Reversely, u have less chance for some bad characteristics to be changed or even be reduced. But nothing is impossible! it's all depends on you yourself."

So...what's in ur mind? ^_*