As a designer, I have come to learn that the details are what makes or breaks a design. I have also learned that most people (viewers/users) don't notice the details that we spend hours on. The flip side to that is that they ALWAYS notice the details we don't spend time on. Are we a little crazy? I'd put money on yes.
Another point is this. The questions you raise are battles we constantly fight. Design is often times undervalued or an after thought. Maybe not at a large client level, but when you get down to the smaller jobs; people expect a lot for a little. Customers want a Nike level design for a Shady Bob's used car price. These details you are pointing out are the difference between the quality of a design. It is difficult for me to NOT pay attention to these details, but for Shady Bob... they're probably not going to get as much time.
When you start skimping on the little things here and there, it adds up and people will start to notice. It's better for my sanity to just do it right the first time.