A common and big mistake beginners make is shoving/calling all-in on the flop with no hand + flush draw.
I used to make this mistake myself and once upon a time thought it was a good play to cold-shove flopped flush draws.
Even if you have the nut draw, 2/3's you will not complete the flush...
To move all-in (calling all-in is even worse) when you have a high card hand and your draw misses 66%
- is awful
While there are
(rare) situations where we do want to make this play, the frequency and willingness with which noobs do this is pretty laughable.