As many of you know Master Yoda had been called many things in his life: Master, Teacher, Jedi, hard to under-stand. All true but here is the tale of how he was called something else.
As you know Master Yoda does not wear shoe. Over his 900 year life that had caused him to build up a massively thick layer of calluses on his feet.
His powers as a Jedi allowed him to see the future and the past better than all the other mystical Force users of his day.
Also as a form of Jedi meditation He also ate very little, which made him rather frail and with his odd diet (snakes, lizards and swamp rats), he suffered from very bad breath.
All this is why some called him (and Jon, I am truly sorry for this) a super callused fragile mystic hexed by halitosis.