I deadheaded from BWI to CHS to start a trip with a flag-tie yessie. Dude pre-emptively tells me he taxies "faster than most" and to let him know if I get uncomfortable. He hits 45 knots groundspeed behind the row of C-17's, but has to slow quickly when we catch up to an RJ. He then goes on various tirades at this point about ATC, other lesser pilots, you name it. Surreal.