From my personal experience (thus does not have statistical significance), it's not the amount of knowledge, but the position. Teachers/professors are a group of people that I interact frequently with (both my parents and parents of my friends are university professors/lecturers), and it just happens that the ones that I know the most are all overconfidence.
Basically they think they know everything, to the point of educating the doctors about medicines when they are in the hospital (as patients). I don't know what got them into this but I found the arrogance distasteful.
Maybe it's in the culture though. Back in the day teachers were respected and the relationship between teachers and students are somewhat closer to father-children than customer-merchant. Now time changes but old habits stay hard.
Basically they think they know everything, to the point of educating the doctors about medicines when they are in the hospital (as patients). I don't know what got them into this but I found the arrogance distasteful.
Maybe it's in the culture though. Back in the day teachers were respected and the relationship between teachers and students are somewhat closer to father-children than customer-merchant. Now time changes but old habits stay hard.