Saw my first 747 in flight in about 1979, when I moved to my first big-city job in Chicago.
What impressed me was how slow and majestic they looked (as eyeballed from the ground in fuselage-lengths-per-second) as they circled the city to join up with the smaller folks for approach to ORD - made me think of dirigibles in films from the 1930s.
My life simply didn't incude a lot of long-haul rides, so only two to report on the 747: CHI-SFO on United in 1982, and SJU-STL on TWA around 1992. No complaints, and glad I got the opportunities.