You are what you are and will always be and hence its very important that you do what you are not, to get used to things which you are not comfortable, which you feel is very messy, difficult, frustrating.. And when we are used to what we are not, we can face the world much more boldly, with lot of confidence. We don't get bogged down by those messy things, instead we get the courage to face it head on..
So what's your fear, what you don't like, what you think is messy, frustrating. Do the extreme for sometime, say you don't like confronting anyone, select one group and go head on. You don't like mingling with groups, take up something which you love where you need to meet lot of people, say social service. Do you find it difficult to keep your house clean, go for community cleaning, am sure things will change for ever. Are you afraid of heights, go trekking on a mountain.
We can live in fear for ever but do the extreme of the one which you wish to get rid of, say for a period of three months, am sure life will be lot better..