I just took a quick personality profile test and the results seem pretty accurate.
The ISTJ personality type information is relatively close, with a few differences.
“ISTJs are very loyal, faithful, and dependable. They place great importance on honesty and integrity. They are “good citizens” who can be depended on to do the right thing for their families and communities. While they generally take things very seriously, they also usually have an offbeat sense of humor and can be a lot of fun – especially at family or work-related gatherings.”
And the fictional ISTJs I feel most like are Joe Friday and Puddleglum. It says Math Teacher is a good choice. Imagine that.