Listen, I'm not going to defend the attitude you've encountered, it's not good at all, it's quite possible that he needed to make his numbers up for the month end and sell some cars and the thought of following you about while you make your mind up was a waste of time for him.
This isn't to excuse it, moreso explain it.
Like I say, I've never suffered a poor attitude from a salesman, maybe that's a reflection of my laid back attitude, who knows.
Can I ask, what do you do for a living?
I'm an old age pensioner. Thirty four years police service some as a detective, most on traffic patrol - motorbikes and cars - largely on motorways. As such I am well versed in dealing with "doughnuts".
Been retired from the police for twenty years after which I worked on ambulance patient transport, which was interesting as I was able to see the long-term effects of RTA injuries, some of them seriously life-changing. It's why I rant sometimes when I read some of the willy-waving threads on here.