Then why do I spend so much time fixing bugs in code where the concept was complicated to the nth degree so it could be written in five lines instead of ten?

I agree that fewer lines of code is better, unfortunately if you hold that concept in too high a regard it's easy to make a mess. Some programming challenges are complex and the complexity can't be avoided. Sometimes solving that problem in fewer lines of code makes the problem even more complex. Just because the complexity is moving from the code itself into the developers head doesn't NECESSARILY mean that it will be less prone to bugs.