The first time I took it, it was a legit' one and super long at a college. I tested as ESFJ. I was so sure that was me. I took it online later and tested ENFJ for some reason. I actually think I have a developed iNtuition as far as my type goes, because I enjoy deep subjects and talks, especially with my INFJ friend! I also question things a lot; ISFJ's are said to be conventional and traditional. That's not really me. I also look for deeper meanings in life. This is all unlike my ISFJ grandmother and what I've read about our type. My whole family is composed of Sensors, and none of them care about "deeper" meanings in things. I'm without a doubt a Sensor though. I know that I don't have that innovative way of thinking that iNtuitives carry. I wish I could be that way for the sake of my intelligence, but I know I'm a Sensor. I know the way I think: it's concrete, and I have a little trouble grasping new concepts in school if they're not explained in precise detail. (I'm sorry if this offends any of you. I might not have the best understanding of iNtuition vs. Sensing; I'm just saying what I've experienced and know about myself. I'm not by any means speaking for all Sensors.)
I realized a couple of months ago that I'm truly an Introvert who tried hard to be an Extravert. It was expected of me by my entirely Extraverted family and my Extraverted best friend.
As a child, I was Introverted as could be. I had to adapt in school though and reach out and make friends. I began to realize that I enjoy my time spent alone. It's actually the MBTI that made me realize my true nature and how to be comfortable with it.
There was also the fact that ESFJ's are not afraid to tell their true feelings, while ISFJ's prefer to keep them inside. I thought I was like the ESFJ but realized that I, for the most part, only tell people how I really feel about difficult subjects if we're talking over messaging, because it's so easy. A lot of my friends live far away, so that's how we talk. I realized recently that that isn't really who I am. Like an ISFJ, in person, my true nature is to keep my feelings inside to protect myself and mostly to keep peace. Discovering my true type is helping me to be more accepting of who I really am (also who others are in my life but I digress).