Yeah customers are "supposed to be always right"
But at the same time
If a customer acts like a jackass (first...or for no reason), to every person providing them service
.....Then don't be surprised if you run into "that one" employee
Sometimes employees have a way of being on some slick shit
For example:
You want to be a complete asshole to the Nissan/Infiniti service employees..........okay

Just giving attitude for no reason, just because your an "entitled customer"..........okay

Don't be surprised if they do just the bare minimum... "just their job & nothing more"
You bring your shit in for a simple oil change
Nissan tech notices one of your hoses getting brittle
And likely to fail in the future, because this particular part is a common issue with this model
Option #1...bring it to your attention, before your warranty runs out, & save you some money in repairs
Option #2...just do my job & change the oil, for mr asshole customer
When the shit fucks up 6 months down the road after the warranty, & costs thousands to repair, then thats yo fuckin problem
Because the burden of proof will be on the customer to PROVE the part was going bad before the warranty, etc, etc
So good luck with that "formal complaint letter"