It's been so long and I feel bad for the fans that didn't witness those teams. Man, back then a loss was really rare. During that three-year super bowl run Miami was 44-6-1. Even as good as New England is, I'm not sure that will ever be matched.
Miami had the winning formula back then, strong defense, smart players, amazing running game and Don Shula. That formula still wins in this league, although it's more geared towards the passing game.
My brother is a Minnesota fan so even more difficult for him. I believe 12 teams have never won a super bowl and that's a lot considering this is super bowl 52.