Yeah nothing to do with the vibration, noise, overcrowding and crap reliability!
Having worked on the railway in the 1990s, almost every train has suffered any and all of that, even the Class 90s and 91s
I had a short stint at ICEC and drivers started referring to me as "The Jinx" as almost every train I worked on would fail, run late, have some form of technical fault, or some other problem
I can only remember working a handful of trains that were actually "on time", although a few did arrive early, but usually due to a diversion that had been cancelled and so we were able to use the normal route
I took day trip to London a few years ago, on a very tight schedule, with just 30 minutes to get from Euston to Kings Cross, and all those services ran on time, from Glasgow to Euston, Kings Cross back to Glasgow with the same set back to Kings Cross, and finally Euston back to Glasgow again
On balance, every Class 390 I have been on, so far, has been "on time", certainly nothing more than 15 minutes late