I've realized something really insidious about aikido training: sometimes people do a technique the wrong way, and they tell other people to do the same thing. To prove that they are right, they intentionally fall when I do it "their way", and apply a lot of blocking/resistance if I'm doing differently.
Don't do things differently, do them right. You know the old saying: "If do right, no can defense".
And grow a handlebar moustache