Pamela's would do 80 in 3rd, we were going up north (her family were from Blackburn) and hit a contraflow on the M1 which slowed traffic to about 25mph for 1/2 a mile then slowly sped up til we cleared it after a couple of miles more and went back up to cruising speed, after a few miles she said "why is the car making a funny noise" and so I turned the Cassette down to have a listen (I'd just given the car a full service) then asked her why she was still in 3rd gear. to be fair we'd been nattering whilst in the contraflow, just the normal stuff like "look at that dickhead" and "Why is he changing lanes when the signs said stay in lane" etc. and the speed had very gradually built up to about 50 when the roadworks finished so she had been a bit distracted.
mind you the car enjoyed it, it was running like a sewing machine after that good 'blow through'* and me changing the oil and filters and setting the mixture and timing at my mates fully equiped workshop.
* Known in the trade as an 'Italian tune-up'