Do people on Grayhound busses clip their toenails in sight of everyone? Is there open drug use? Do people bring bluetooth speakers and party in the back?

In that case, yes, Flixbus is similar to Grayhound.

Did this happen on Flixbus yet?

https://en.wikipedia.org/wiki/Killing_of_Tim_McLean

There have been some grisly attacks on London buses (my home town) - one of the reasons I avoid them late at night:

https://www.independent.co.uk/news/uk/crime/i-feel-sorry-for...

https://www.cps.gov.uk/london-north/news/two-youths-jailed-b...

https://people.com/what-happened-in-the-july-7-london-bombin...

We have plenty of beheadings in Europe but not on a Flixbus.

Flixbus owns Greyhound now