The thing I regret not doing was traveling to Berlin back then and crossing over into the east. There was an effort going on to persuade us to make trips over there so we could keep established our right to do so. But I wouldn't have been able to take my family, and I'd have had to sew stripes on my Class A's, so I didn't do it.
I finally made the trip to Berlin a couple of years ago. Saw the "Checkpoint Charlie" museum. You'd be hard pressed to find where the wall was in the city, but I think I caught a glimpse of it from the train on the trip through. Apparently that's the only place it still exists is through farm fields outside of town.
One of the most emotional moments in my life was watching the Berliners dancing atop that wall in early 1989, around New Years if I recall. One guy wailing away on a trombone still sticks in my mind. It was a two shirtsleve moment at the time and I can still get a little choked and misty just remembering.