The passenger count is so heavily influenced by factors outside of the bus driver’s influence that this example doesn’t make sense.

Passengers don’t abandon bus routes because the bus driver didn’t smile at them. They abandon routes when the schedule is inconvenient, there are better alternatives to the bus, the fare is too high etc etc. None of these are in the control of the bus driver.

My old bus route to work used to amuse me greatly because on it there were two drivers who were the polar opposite of one another. One guy I assumed had previously been the pilot of a commercial airliner because he used to greet everyone who got onto the bus with that sort of demeanor and make announcements etc. Always brightened my day. The other guy was the grumpiest piece of shit bus driver I've seen anywhere in my life who would frequently berate passengers and oftentimes frighten unsuspecting foreigners. Everyone who needed to get to where they were going showed up and took the bus regardless. It's about the least important variable there is and it averages out to getting a reasonably OK bus driver almost all the time across the different busses you take and the different times of day you take them.