My weakness is the way that flight characteristics of javelins change depending on what I'm trying to do.
If I'm on horse, then any time I throw, the javelin will fall short, unless I'm in 2 hander range of the target.
Any time I'm on foot, and I throw a javelin, it either falls short, or way overshoots. I adjust a hair to make it work, and it goes way-overstated in the other direction!