Forrest is a simple minded fellow, but he is good at one thing: following orders. Jenny told him to run as a kid, and he ran so fast he broke right through his leg braces. She told him to run if he encountered danger at Vietnam, and again he outran the entire ambush. His drill sergeant told him to disassemble his weapon, and Forrest took it apart so fast he set a new company record. Why? "[Because] you told me to, Drill Sergeant?" How did Forrest get so good at ping-pong? Because the soldier who introduced it to him told him just to never take his eye off the ball. It's the reason why Forrest found the Army so easy, because all he ever had to do was follow their orders. So while he may be handicapped in thinking for himself in life, give Forrest a command to do and he will do it to the highest of human potential.
Forrest: (telling Jenny about his Medal of Honor.) I got it just by doing what you told me to do.