I admire people that can express themselves freely without any emotional worries

Whenever i see people in the discussion boards debating or expressing their opinions towards a certain subject using an extremely direct tone even if it might sound offensive, i kinda envy their guts, its like they dont care about any consequences that might follow afterwards and they just relentlessly voice up their views. While for me, i couldnt express myself freely without feeling hyper conscious and anxious of the opinions from others. Argh...

There are books on persuasion. Try them. Also debating is something that can be learned. Listen to good debates and see how the parties debate respectfully, and what expressions they use, especially when addressing others views. Confidence plays a role in discussions, without it, the presented view will be viewed weak, even if it is correct.

I am very opinionated and use this board to practice discussing things in a civil way. I am a hothead.

I think you just need to try. Practice makes perfect.