[T.B. Yoits]

In fact, a high IQ may even be a handicap.

True, because the burden of knowing can be huge whereas those walking around oblivious have not a care in the world.

[The Duke]

"True, because the burden of knowing can be huge whereas those walking around oblivious have not a care in the world."

Also, because a high-IQ person can spend years absorbed in solving a single problem to perfection, while someone else solves the same problem sooner (and maybe less perfectly).