"...American (pilots...)...dangerous". Hmm. I manage perfectly safely over here with their system, flexibility once again.
I'm sure not ALL pilots are the same whether it be Yanks/Brits. But as ATC if the pilot replies a required readback with "roger" that's not f**king flexible, that's stupid and annoying and very very unprofessional. I've had so many US airlines replying with a roger that I feel I should report the guy. Just do it! (that saying is from Seattle, US right?)