From the movies:
- Qui-Gon fails (multiple times) at manipulating Watto on Tatooine in EpI
- Luke tried using it on Jabba in EpVI, to no avail
- Mace Windu failed to manipulate a Dagoyan to allow him access to the Queen's chambers on Bardotta
- Ahsoka Tano tries to get info on a potential hostage from a Mandalorian Security Officer, but fails
That makes at least four species that are resistant or immune to the Force Mind Trick, and there's probably many more. So my question is: Why don't the Jedi know who's receptive and who's not? Is this never a subject during their training? Why can't they sense when a creature isn't weak-minded enough to use this ability on?
Why isn't it as easy as:
A follow up question would be whether or not Dark Jedi or Sith have this problem, as I've only found Light Side examples.
Legends answers are acceptable.