I knew a lady who had a lesion on her frontal lobe. She had been a teacher and developed it before she retired. She had to take early medical retirement because of it.
Unfortunately, her lesion progressed pretty quickly and it wasn't long before she had to be admitted to a mental hospital because of her extreme mood swings. It was very, very sad because she had been a great teacher and such a nice person. No one deserves that kind of illness and it was hard watching her decline.