Proving people wrong runs out of fuel. Proving yourself right never does.

Motivation borrowed from other people’s doubt works well and works briefly. It depends on them continuing to doubt you and on you continuing to care, and both of those fade. Once the people you were answering have moved on or gone quiet, there is often nothing underneath. Wanting the thing for your own reasons keeps working after the audience leaves.

Write down why you would still do this if nobody had ever doubted you. If the page stays empty, better to know now than in three years. Use the anger while it lasts and build something steadier beneath it.