Because every time I ride in Morgan cars, the bar, which is either not padded at all or isn't padded nearly enough, is already jammed into my leg before the ride even leaves the station or does anything. There isn't a higher position on the bar that would allow me to ride, so that's my option-bar jammed into thigh or no ride at all. Then once the ride begins I feel each and every bump, turn, jostle, you name it directly jammed into me. Not fun or comfortable. If it was just forceless I'd be fine with that, but alas it's just uncomfortable and painful instead.
And because of how the cars are designed, when we're boarding the cars I also have to deal with the added annoyance that for some reason the bars in each car are all on the same system, so if somebody else in a different row starts trying to put the bar down before I'm situated, the bar starts coming at me when I'm just trying to sit down. I shouldn't be affected by what little Johnny one row ahead of me is doing with his lap bar. That's just bad design.
I'm sure Giant Dipper would be a fun ride without the Morgan trains, but I absolutely cannot stand those trains and they simply do not work for me. And so unless they switch out the trains I will never, ever ride either Big/Giant Dipper roller coaster again-the only coasters in all of California that I have done that I would say that about.