I think most people do that, so they don't get full of themselves and get a large ego. That's my 2 cents any way.

Better than thinking their art is the best all the time.

If you're not confident in your art, then there is a need to improve. If you are completely satisfied with how your art is, then that's where your skills plateau.

for me people say they love my work but in my mind it look more amazing better details and just wow, but when drawing it look like crap and drawing more just make me feel bad. some people really want to match what they seeing in there mind and even when it great they want more until perfect but sometime when it perfect and they draw something new it dont feel as great as the last one and they go crazy and get depress. some just try doing to busy over working them self to the point they have to stop because they know there drawing being to look lazy,