I deal with technical issues for users and have for over 20 years all around the world. In my experience 5% is too high. There are certainly problem customer,

I deal with technical issues for users and have for over 20 years all around the world. In my experience 5% is too high. There are certainly problem customer, some from frustration for things not working, some more a language barriers and then the jack asses - I’d say that 80% of the work is on 10% of customers which skews the results further. I can only think of a handful, less than 10 customers I wanted to fire and only one who was such an asshole I did in those 20 years. If you are able to solve the problem of the user they normally turn around.