How do you deal with boredom when actually 'travelling'?

Everybody I've spoken to who has been travelling unanimously agree that the worst part of travelling is the actually travelling to and from places. There are a few reasons that usually get given such as cramped hot buses, no breaks, overcrowding, long periods of time doing nothing and boredom. I was wondering how people actual combat this boredom? Do you have a favourite book? A favourite playlist? Do you write a travel journal? How do you stop the 'travelling' becoming a negative experience?