Socializing
A lot of us do not like talking with people or are a little bit socially awkward and just do not know how to do it. Well, it seems like you can not avoid people forever and remain a loner, you just need to have a few friends and get out there once in a while.
It is not for them, it is for your mental health because loneliness and isolation are not good things at all. It can have a serious negative effect on our mindstate and we want to avoid that at all costs. Going out once a week in a social setting should be enough.