Yep, nasty shit. One 75mm A/T gun hidden in the hedge backed up by a squad of infantry with an MG-42 and you could tie that road up for hours.
And you wouldn't know they were there until they opened up. And the bocage was ubiquitous to Normandy.
I suspect you're right about Omaha in the American mindset. The other fuckup there was the reliance on duplex drive tanks - most of which sank before they reached the beach.