When you come out on the roof of the museum during the first Minutemen quest, there is an inaccessible raider on the roof across from you. There is no vanilla way onto this roof. If you kill the raider before (if) he jumps down you can not loot his body. Also good neighbor, if you are trying to get inside, sometimes you take a wrong turn and end up at the wall of the town, but not at the front gate. Instead of backtracking, one could simply climb the wall. When saving Valentine in the vault quest, there is a hole in the floor, and without a jetpack, you can't get back up once you go in, which is weird because I could grab a chair (there is one nearby) and climb back up to the upper floor. There are many situations in which I have found the ability to climb scale or jump would be quite useful and beneficial