properly judge the speed required to clear the jump.
lack of confidence to attempt the jump to start with, or to try it again.
in the above list, one of these, always gets us, and some of them are just part of the nature of jumping. for example, you are not going to be able to necessarily always judge your entry speed perfectly. you are not always going to land perfectly. the wind may still catch you out.
welcome to jumping! simply put, you are going to crash sometimes, and if you are too scared to crash, then you may never jump anything.
it is also important to note, in a race, the jump 