I've been extremely interested in MBTI for a long time. My interest in it has been based on self-validation for the most part. It provided understanding, even deep insight, for an odd-one-out like me.
Not long ago I read Lenore Thomson's book about MBTI/typology and I was extremely excited about it. After I had read it, I felt kind of empty... like the whole subject had lost its meaning to me. I suddenly felt that MBTI is worth nothing.
I suppose that feeling came from the fact that I could identify with every type description in it. It didn't feel like 16 distinct boxes anymore, which plays key role in its usage as a tool. I dunno. Nothing was clear anymore, although it was supposed to be even clearer after such focused literature.
I'm still interested in MBTI. Just not as much. It's difficult to let go of it. I'd still like to know the type of any new friends I make... the urge to test them is strong... but all in all, I've lost a lot of respect for MBTI.