Key word here is "probably'. I made multiple 16 hour almost non stop trips through Europe, and it's fine for me. LA to San Jose and back in one day, with useful

Key word here is "probably'. I made multiple 16 hour almost non stop trips through Europe, and it's fine for me. LA to San Jose and back in one day, with useful activity in SJ (working in the data center servicing our colo hardware) is almost a monthly routine now, without the need to book a hotel overnight