When I first starting flying places in 1967 I had no idea what to expect. The noises, the groans, the multitude of other things that are new. My Father had been a mechanic on the infamous P47 aircraft during the second world war. He never in his entire life ever actually rode in a plane. I heard repeatedly how he knew what could go wrong with them and therefore would not fly in one. Can you imagine how nervous I was on my first flight. One of my only two thoughts I had was there was a lot of time between 1944 and 1967 so things were probably a lot more advanced over the years and second, even though I wasn't hoping for planes the crash the more they happened previous to my flying, the better my odds that things were going to be just fine.
One thing one must remember is that Boeing may have built them but they do not maintain them. That is something that the airlines do, so if I were to be concerned about it I would probably look to see if any particular airline is having problems and not blame the builder until it is determined that the problem was engineering.
There are a whole lot of people that have flown millions of miles with no problems. I have probably not done much more than the cumulative distance of about three times around the world. Never had a bad experience with equipment. I did occasionally find a few people that worked for them to be less than enjoyable.