I have a friends who I know and have known who come across as quite composed and calm and unfuffled..?

like they are controlling their emotions and themselves quite a bit, I really like this personality type, the cool calm and collected type. I have never really been that way, I think these people are most respected and liked in my eyes mainly because of these personality traits they have. I think I have many good traits naturally myself, but recently I have been described by 2 people that didn't know me very well as "bubbly" - I couldn't hate that description anymoree! and have never tried or wanted to be that way..and so my question is, if you are described as cool, calm, collected and emotionally detached yourself, then is this something you mould yourself into being, or is it 100% natural? Do you hold a picture of how you want to be in your head and then be it, or is it something that happens naturally? I have a big problem when it comes to expressing my emotions they seem to leak out of every expression and conversation I have as well as laughing too much at times and I just think that cant be too cool (like cheryl cole who grates on me!) and do you think I/a person can change or is it just the way they are, basically!?? Any ideas, experiences and stories would be very helpful.. thank youu