What's the biggest mistake new poker players make?

I've been reading more about poker strategy, and one thing that keeps coming up is the importance of patience and discipline. In your opinion, what's the biggest mistake beginners make? Is it playing too many hands, bluffing too often, or ignoring position at the table? I'd love to hear advice from more experienced players and learn what helped you improve your game.

Definitely playing too many or too little hands from different pre-flop positions, also not raising enoght but deciding to limp (call and not raise first in) too often.