LeBron James says Cavs owner Dan Gilbert "completely bashed" him in that infamous 2010 letter about LBJ leaving for Miami ... and Bron says it was so disrespectful, it almost stopped him from returning to Cleveland in 2014.
LeBron opened up about the letter on Uninterrupted's "The Shop" -- which was shot during All Star Weekend but released today.
Gilbert's letter was loaded with insults -- even referring to LeBron as the "self proclaimed former King."
In the video, LeBron says Gilbert "completely bashed me and disrespected not only me as an individual but disrespected my name.