These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
What an Idiot: A British tank officer tells an incredulous American paratroop commander that they won't immediately press on to Arnhem after taking Nijmegen because of some trivial reason. Note that this is Hollywood History. XXX Corps needed time to marshal their forces and resupply their leading elements when Nijmegen bridge was secured.
Hardly trivial. The tank officer clearly states that they couldn't advance without infantry support, which was tied up in Nijmegen.
Actually they had infantry support. The American paratroopers were raring to go and they could have easily provided the necessary support. The reason the Brits didn't advance was because Montegomery was an inflexible general who ordered the tanks to wait for SPECIFIC support rather than using available resources. The guy was the military equivalent of an old maid, refusing to go on the offense without a significant advantage in men and material. In fact many people believe that if Patton (Monty's opposite in almost every way) had been in command of Market-Garden then it would have succeeded.
A more appropriate example is an Allied officer bringing the entire plans for Market Garden to Holland with him, where they fall into German hands. Field Marshal Model then dismisses the plans on the grounds that they're obviously a ruse.
Note though that two previous Allied offensives on the western front — the Normandy and Sicily invasions — had disinformation campaigns the Germans fell for hook, line and sinker. Model would have been aware of this.
General Sosabowski points the holes in the operation plan, only to be ignored by the rest of the staff.
Maj. Fuller receives intelligence that there is a panzer division in the area. He corroborates this with aerial photos. No one listens.
Field Marshal Model actually says this of the British. General Bittrich asks him if they should ready the bridges for destruction, but Model laughs this off. "They're not after the bridges! If they were, do you think they'd land eight kilometers away from them?"
Montgomery or Monty being "very proud and pleased'' with the result as he apparently believed Operation Market-Garden was "90% successful." Urquhart (Sean Connery) is appalled, offended, incredulous and anything else you can think of upon hearing this from Browning (Dirk Bogarde).