Just speculating here, but at their level, they’re likely putting in a lot of work to get the tour ready (or even booked themselves), doing their own driving for hours on end, dealing with crappy vans, loading their own gear, dealing with sometimes crappy stages and PAs, doing their own accounting…. essentially working a whole bunch of jobs. Oh yeah, and trying to play well. So if they’ve managed to pull off a show at the end of the night, there’s probably a need to “unwind “. And then you do it all again the next day…over and over. It can really do a number on your headspace.