Graffiti aside, what is it trying to say? Is it from a certain study, does it mean "on average", is it a hard and fast rule that makes you male or female, what part of the world was this studied in, what demographic does it represent? It's just vague and moronic and frankly deserves to be graffitied.

These are just getting stupider and stupider......

Nope, music has gotten worse and worse. Its been a disturbing trend that the record companies seek out less and less talented artists to capitalize on a model which sells more records but produces blander music. Need proof? Ok, tell me who is as talented AND as popular as the Beatles, Led Zeppelin, or Pink Floyd and is making music today?

In the deleted scenes he actually disappears from the future once he returns, erasing himself from the timeline. The logic here is that the timeline must have been slowly fading and altering itself like it threatened to do to Marty in the first one, and didn't complete until Doc and Marty returned to 1985.

The time turner CANNOT change the past. JK Rowling was very careful not to allow this so people wouldn't poke holes in it. But clearly she overestimated peoples intelligence >_<