all (one's) taste is in (one's) mouth
One lacks appreciation and discernment of what is refined, beautiful, or excellent—e.g., "taste." Did you see that tacky dress she had on? Yikes, all her taste is in her mouth. Do not ask Joanna to help you decorate your new house—all that girl's taste is in her mouth, trust me. If you really think this is a "classy place," all your taste is in your mouth!
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.