A regular told me my neckline work was 'too soft' and it made me rethink everything.
He came in last month for his usual cut and said, 'Viola, the sides are sharp but the back looks like you got scared of the razor.' I realized I'd been rounding off the neckline too much, trying to make it look natural. Now I use a straight razor for the final inch and keep the line crisp. Anyone else get a piece of feedback that totally flipped a basic technique for you?
Read a barber's blog post once where he said the biggest mistake beginners make is starting the fade way too high. Leaves no room to blend it down, so you get that harsh line. He called it the "helmet head" special.