Presta valves should only be available by prescription in the United States. Every day, thousands of bike shop employees are called on to explain and apologize for that weird little metal demon that stands between so many hapless riders and proper tire inflation.
Filling a tire with a presta valve is simple. Remove the cap (if you bother to use it), unscrew the little metal tip on the valve core, shove the pump head on there (thumb lock it if your pump has a thumb lock), inflate to the desired pressure, remove the pump, screw the core shut and you're ready to ride.
That process is discouraging enough. If the rider wants to use a compressor with a common air chuck, then they have to use the dreaded Presta Valve Adapter. Now it gets really complicated. Remove the cap, unscrew the little middle part, thread the adapter on the right way around, inflate with the air hose, remove the adapter, screw the little middle part shut and off you go.
TOO MANY INSTRUCTIONS! WHY? WHY? WHAT'S IT FOR? WHY IS IT BETTER?
Over a long career in the bike business we strive for the right balance of education and commiseration. Some riders learn readily and become Presta People. It's the Attack of the Presta People! Look at them with their weird little tire valves! Others are completely disgusted by the inexplicably complicated device. We adjust our approach to find the customer's comfort zone.
For the Presta haters I say something like, "Yeah, someone ought to get into a time machine and go back and find the guy who invented that thing and kill him as a child so he'll never grow up to invent it." Or I'll say it was invented by Napoleon as part of his quest for world domination and somehow survived to the present day.
The best news a presta hater can get is that we can drill out most rims and change the tubes to end their torment forever.