LorgSkyegon

Answer: It seems more like Jenny realises that she is a screw up and doesn't deserve the love of Forrest. She left to get herself together in order to be worthy of him.

LorgSkyegon

Answer: Forrest had mental issues. Jenny slept with him because she thought she loved him (and she realises later that she did), but didn't think that Forrest loved her back because he wasn't capable of understanding that kind of love (and she realises later that he did). She then remembered that her dad sexually abused her when she didn't understand what was going on, and she felt like she was behaving the way her dad did (remember Forrest's look of fear and discomfort?). Jenny then felt guilty and ran away because she didn't know how to deal with the guilt.

Answer: People who were abused often have issues with trust, and they can have difficulty forming healthy, stable relationships. They are often drawn to problematic relationships - for example, Jenny's boyfriend, Wesley - because these situations are familiar to them.

Answer: The Army doesn't issue IQ tests upon enlistment. Given that Forrest had a college degree, and passed basic training with flying colors because of his amazing ability to follow orders, he would be allowed in just fine. And Bubba didn't have a cleft lip, just big gums.

LorgSkyegon

Answer: I can't even guess why you think a cleft lip would disallow someone from being admitted into the Army, or anything/anywhere else for that matter.