I gave up on Glocks years ago. Three main problems with them: mushy trigger pull, yes you can make it lighter but you can't make it not mushy (unless you use one of the CCF metal frames, but really, when you get to that point it's time to admit defeat).
They still put plastic sights on them after all these years of complaints about the front sight getting mangled, so you have to spend extra money to keep your sight picture consistent, plus the front sight is staked, not dovetailed, which is gruesomely annoying.
The 9mm/.40/.357 models crack their slides, because the serial number stamping under the ejection port weakens the slide, and I've lost count of the number of cracked Glock slides I've seen that have cracked in that spot. All they'd have to do is move the stamp further forward, but I'm sure they don't because then everyone would ask why.
Oh yeah, and the breechface looks like it was cut with a Mongolian horseshoe grinder, although that is more of an aesthetic problem.
Irritating problems that could be easily fixed just put me off Glocks, makes me thinks they must either (a) be stupid or (b) too scared to admit their mistakes.