Major ports always have been and always will be complete shit holes. Dover is no better or worse than Calais or Zeebbrugge.
Boulogne was a shit hole when it was an active ferry port but now its a lovely little seaside town with some great fish restaurants. Well worth a visit.
Ten years ago, I got lost in Dunkirk, trying to find a 'hotel' with the aid of an inadequate map. I asked a few people, but just couldn't understand all the complicated directions.
I saw a bloke walking a little dog and decided that he was my last inquiry, if that failed then I would sleep in the van. He really did have no English and my French still wasn't enough. "Wait here", he said, "I'll be back in a minute" - I thought he was just going to draw me a map or something, but he came back in his car and had me follow him through the backstreets for about five miles, right to the door of the place.