I wonder how much time I've spent throughout the years looking at loading screens on my computer. Whether I'm waiting for a video to buffer or a game level to load, I often find what's happening on my screen to be much less interesting than it was the minute before or will be the minute after.
I use long loading screen waits to plan out my day and consider if the media I'm trying to load is really worth the effort. I'll read a book during really long loading waits. I might even write a blog post.