In defence of bike shop sales staff, having had the displeasure of being one myself for a bit, you are expected to have years of knowledge of stuff, loads of enthusiasm and passion for the job, yet you are paid crap wages, relatively. So, most bike shop staff are just folk doing it until something better comes along.
Me, I did it cos I needed a job and I could get stuff cheap. I din't do it for the sake of any customers ffs! All I asked was that people gave me a bit of respect and I'd respect them back.
The amount of crap you get off tossers who come in, and for what? Six quid an hour or so? Sod that.
'Where's my bike/stuff I demand it this instant!'
Mate, do you genuinely think I really care? Seriously? Hold on, I'll just go out the back to have a look for it (and to chill out for 10 minutes or so, make a cuppa, have a poo maybe, chew the fat with the grease monkeys...) Nah sorry it's not in you'll have to come back next week.
If someone had come in and asked me about a flippin hybrid 29er, I'd probbly have sworn at them....