I think it's absolutely fascinating! I've been at it for three(ish) years with Myers-Briggs, plus a couple years prior with the Five Temperaments (Sanguine, Choleric, Supine, Melancholy, Phlegmatic)...it gives so much insight into life.
I seriously think I've asked almost everyone I've been close to in the last three years to take a test at some point

You're not alone.
As for ESFJs, it helped me tolerate (negative connotation there...can't come up with a better word) them a lot to just get a better understanding of their inner workings. It also encouraged me, after learning more about ESFJs and getting some input on here from ESFJs about my specific situation, to pursue resolution with an ESFJ family member. Gave me a more "rounded-out" view of her, I guess.
It's hard to deal with people now, after understanding so much about how people work and
why, who aren't familiar with, or don't believe in differences in personalities. It's like hitting your head against a wall trying to explain that no, we're
not all the same, and yes, we may actually have completely different methods and understandings within the same issue.