Sorry, but my best ones are from (American) football, from some of my high school coaches.
"You're all crunched up like a G(*&$mn animal!"
(Critique of our punter's technique)
"You can't make chicken cacciatore out of chicken s&^t."
(Summing up our marginally talented QB's inability to execute a gadget play)"
"Don't be a stump on a log!"