/ic/ - Artwork/Critique

Why is pic related considered bad?

Asking because of a few posts I read over there : >>2432262

>work in fabric store
>somehow a copy of a Chris Hart book ends up in our shipment
>hide it every time it makes its way to the front of the shelf
>working register one day
>woman comes up with a stack of sewing books
>this abomination is on the bottom
>do I tell her? What if she gives it to a son or daughter who really wants to start drawing?
>but what if she's just buying it for someone with only a passing interest and it's not my place to intervene?
>hesitate and stall for a good 2 minutes.
>"Here's your receipt, have a nice evening"
>regret it every day