When the PD morphed into "no warp drive, no contact", some early TNG episodes stick out like a sore thumb. I could just swallow it being revised since Kirk's era, although I can't see any non Federation races paying it any heed.
That episode with Worf's brother, where Picard stands around while a planet's civilization was dying as their atmosphere bled away pissed me off though. Definitely a WWJTKD? moment. ;)