I teach Windows Forms programming, and now ASP.Net (essentially the same thing, except you view it in a browser) and I am dismayed that students seem to spend an enormous amount of time straining at gnats, trying to get picky details of the appearance correct. This involves them attempting to do extra things, like adding backgrounds, and putting images in to buttons and carefully positioning and sizing everything. This eats up masses of time and energy and they constantly ask me for help with details that I know nothing about, like obscure subtleties of CSS and so on.
Is there some way to get students to focus on the point of a lesson, which is to understand programming concepts, and not just stare in fascination at the colors and shapes on the screen?
(I learned programming in a command-line environment, without Windows or web browsers, so I am at a loss as to why all of this is so interesting to the students. My attempts to add even small enhancements to appearance for my demonstrations are such a time-sink that I tend to drop them in favor of getting something to work. For example, try to change the color of a Jumbotron.)