Spent 6 hours trying to beat the tutorial level in Ghost Recon because I missed the 'crouch' prompt in the corner.
Thought I was terrible at stealth games until my buddy pointed out the tiny text on the loading screen saying 'tap X to crouch', and then the whole thing took about 4 minutes to finish.
Wait, you missed a whole UI element for six hours? That's brutal, I would have rage quit after the first 30 minutes of that nonsense. It's wild how easy it is to overlook those tiny prompts when you're focused on the action...