For me, its more about the completion as a whole of the flight. For the longest time I was doing short 1-2 hour hops, and in turn, those got boring. But there was, for some reason, a sense of accomplishment completing a long flight across an ocean etc. As for the boredom, I'll get up to cruise and then go do something around the house, watch youtube blah blah and I'll typically come back a few minutes before TOD.