Never get a terrier.
Terriers are smart, funny, lively, often silly dogs that will bring you great joy but at the same time terriers are smart, snarky little bastards that will challenge everything you do or say. They learn the rules so they know what they're breaking. They constantly push the envelope. The good thing is, if you correct them they don't get offended. "No" isn't a negative to a terrier. It means they need to rethink things and try a different approach to get around the rules. It means they've learned how to push your buttons and will do the unwanted thing often -- usually for comedic purposes.
My dog isn't allowed in the kitchen. That's where the cats eat and it's where the litterbox is kept. There's a gate in the doorway between the dining room and the kitchen. The cats can go through the bars or jump over it, but the dog cannot.
Sometimes when we leave the gate open he'll sit there and stare at the gate as if it were still a barrier. Sometimes he'll whimper or fuss. Sometimes he'll wag his tail very hard and bounce and do his "look at me!" dance.
Sometimes he'll silently put one paw across the line and stare. Waiting. Daring you to say something. If you don't (or if you don't notice), two paws will cross. He'll just stand there like that -- technically not in the kitchen, but not NOT in the kitchen.
And then if you look at him, he'll back up and give you this innocent "Oh, was I being bad?" face.
He will be bad on purpose. Sometimes he gets jealous of the cats. If I'm reading and I have a cat in my lap, Cardiff will purposely get into something. He'll pull junk mail out of the recycling basket, carry it into the middle of the living room, and stare at you while he tears it apart.
If you ever see a terrier keeping its back to the room, take away whatever the dog is chewing on. It's never going to be a dog toy or a chew treat. It's going to be your earbuds. Or your fountain pen. Or the book you borrowed from your mother.