1. It tends to be bloated, with developers slapping framework upon framework, creating a mess of background wiring that is prone to a dictionary's worth of issues that will either frustrate the user or confound the person maintaining it.
2. UX Designers approach their jobs incorrectly; they assume they are smarter than the user. Interestingly, this might actually be true on paper in most cases, but the practical reality is that the user needs to do things the user's way, not the way the the developer wants them to.
If we could find ways to smooth those two glaring issues, I posit that we'd see a lot of problems with productivity and workflow melt away. Caveat; I'm not a software developer, so I'm sure anyone who is thinks I'm speaking out of school right now. Fact is, I've worked in a few different industries over 40 years, and one of the biggest thorns always seems to boil down to the software not being quite right for the team/application, so workarounds have to be invented, adding layers of complexity on what is already a decidedly fragile system.