Does the fear of being rejected fill you with painful dread?
Does stop you from doing what you really, really want to do?
Why are we so worried about being accepted?
It's deeply natural and human to want to be accepted and liked by other people. Human beings are social creatures, who evolved in small tribes where it was absolutely essential to be on good terms with other members of the tribe.
Tens of thousands of years ago, if you were rejected by your tribe for some reason, and thrown out to fend for yourself, you would be very likely to meet a speedy end.
In those long ago and dangerous times, your physical survival was very strongly linked to how well you got on with those around you. You needed the full acceptance of everyone if you were to live.
So you had to nurture your relationships with others, take part in group activities, do your bit, and help others do theirs. That's why it makes sense that we all still have a deep primal instinct that it is really important to be accepted.