Armchair critic noun phrase
One who tends to make judgments or criticism about a specific topic, but lacks real experience or knowledge about it.
Don't speak as an armchair critic like that! I carry out this task every day, so I've already known the best way to complete it.
John is such an armchair critic. He knows nothing about computers, but when I repaired my computer he kept saying that what I was doing was wrong.
This phrase was first recorded in 1896 , but the concept was around at least a decade earlier.
A problem or difficult circumstance
I'm short-sighted, so forgetting my glasses is a real hair in the butter for my sight.