>>1428439I have never worked at an lbs but I imagine that the problem is simply that they see so many bikes and they're not working on a bike they care about, i.e. a bike they have to ride themselves, that there is just no love put in to the work on your bike. And by love I mean attention to detail.
I see something similar as a software developer. It's why we constantly have to go back and fix bugs, because we forgot to consider this or that detail. Although in our defence production software is much more complexe than bicycles.