this, it's all about stress. i personally got in a job years ago that was extremely mentally exhausting in terms of technicality and also was a toxic environment, worked there for 2.5 years and at the end i had few grey hairs. i took 1.5 years after doing nothing, just gaming, movies, and fucking girls and i noticed the grey hairs recolored again, i even got few and saved them because it was surreal to see in real time
Canada