Do just once what others say you can’t do, and you will never pay attention to their limitations again.
James R. Cook
On you path towards success you will encounter not only internal, but also external obstacles, naysayers being one of them.
Some people just don’t grasp the idea of “everything is possible” and don’t want to leave their comfort zone. Therefore they do not appreciate others to do so. They do not want to see extraordinary things happen and do not want to believe in them.
Do not listen.
Do it anyway.
Shut them up with succedding without giving a damn about their limited views.