This is one of the main reasons I got seriously bored and left the long haul world. BOS or MIA to SEA was the worst, particularly in winter. I much prefer shorter legs. If you do contemplate using Portable Electronic Devices to prevent boredom, make sure you ask the Capt first if they are OK with it and ensure no Feds are in the jumpseat watching you. See 121.542(d); you can thank the crew that overflew their destination by several hundred miles while they were totally oblivious, bidding for next month’s sked.