I used to rush applying thermal paste, sure it wasn't a big deal. Then a customer's gaming rig overheated and shut down during stress testing. I had to redo the entire cooling setup on my own dime. Now I carefully apply the right amount every time. No more return jobs for overheating since I fixed this.
My friend always rushed his thermal paste jobs until his custom PC started shutting off mid-game! He opened it up and found a pathetic, thin layer that wasn't covering the CPU properly. The whole system needed a re-paste and he wasted an entire Saturday fixing his mistake. Now he takes his time and uses the pea method without fail. That experience definitely changed his approach for good.
Honestly, I used to think thermal paste didn't matter much. But seeing a friend's PC crash from a bad job proved me wrong. Now I'm super careful with that stuff.