Man, the really annoying thing is that Elon-haters are so dishonest (refusing to engage when obviously wrong claims are made, repeating things that have been long disproven, repeating hearsay as fact, etc), that it's hard to actually identify any actual lies Elon has made. Meaning, not just exaggerations or failed predictions, but straight up intentional lies.
My favorite is when things are claimed to be impossible, that Elon's lying because the thing is impossible, but then it happens anyway.
Where Elon gets in trouble is he's wildly over-optimistic on a few things, such as AI. He predicted an AGI would take over in 5 years around 2015 or so (so we're 3 years off), and I think he really believed it. That's why he's always claiming things like self-driving, and doing it without sensors or whatever. His paranoia of AGI and his over-confidence on self-driving have exactly the same root cause (believing AI will conquer all). Elon has had so many instances of overcoming status quo expert predictions (whether on solar energy, battery-electric vehicles, reusable launch vehicles, or whathaveyou), that I think it makes him increasingly unable to very effectively listen to experts.
And he's also incredibly gullible and easily taken in by all sorts of scammers, including rightists and just plain sycophants telling him what they think he wants to hear. Which is increasingly what he's left with as everyone else who is sick of his bull has left.