why do people have a tendency to take extreme steps while taking decisions in group than alone? why does this happen?

When your in a group, it is a natural instinct to make yourself seem "worthy". By yourself you are aware of your own strengths and weaknesses. For some people, a personal profile is everything and their reputation must be upheld around others.

Because sometimes I'm a group you can feel peer pressured or it can be less scary to do it if you are with your friends