Fallout WTH moments:
Settlers getting onto the roofs of buildings that actually have no roof access. And that damn cow. GET OFF MY ROOF!
Companions falling off of things that are actually pretty difficult to fall off of.
Dogmeat dashing off and alerting a death claw and then LEADING IT BACK TO ME!
An armless feral doing massive damage. How exactly does that work?
These are only a few that I can remember. There was another that I meant to mention after Zuhl posted about Nick swimming in mid-air. But its slipped my mind at the moment.
OH! I remember what it was!
A Legendary Radstag.