If a LEO waves me through, that's fine - cop has a legal right (and training) to direct traffic...though I still will make sure, to my own satisfaction, that it's clear.
When civilians wave me through instead of taking their ROW, it irritates me - just follow the friggin' rules, people, and no one will get hurt! But every now and then, a motorist will wave me through while I am hanging out, waiting to turn, in the middle of a busy road, and for that I am grateful.