Hello NL,
Trust you guys are good...

So today, I'll like to get your opinion and probably share your experience with any of your customer(s) that felt s/he was right despite being wrong but because of the mentality that " Customer is always right" he/she didn't swallow his/her pride just to admit.

Some of these customers think they know the system better than you.

Customers sometimes are too much to handle, what with their ego, arrogance and honestly their unachievable expectations? Some think they know the ins and outs of a company's products and processes, whereas they're hardly close to getting it right!
A well informed client is one easy client to deal with, but even then there's just another caliber of people that wake up on the wrong side of their bed just to cause havoc for businesses and their employees.
Beware of such, and to companies, please take side with your employees if you value them otherwise it will be the beginning of the end to your company's progress.