Whenever the camera enters a character's house, that character always does something 'to relax' or just in their free time, but they've done it for several years and they're really, really good at it.
You never see a character say "Yeah, I paint" and then see horrible, ugly, two year-old style paintings strewn over the floor. There's never a bunch of misshapen wooden dolls on their desk, or a dead bird stuck in a birdhouse gone awry.
There's also never any residue; he or she's never missing a finger from woodworking accidents, have paint on their hands, or a hurt knee from tripping on everything strewn on their floor.
I'd like to see a movie where some girl's apartment has a bunch of ugly, monotonous pictures of walls, and she's incredibly proud of her 'statement' but in reality they're just pictures of walls and the main character has to break it to her. If the main character is a guy and thinks he's in love with her before he seeing the product of her idle hands, it would be even more realistic, but I'd settle for reuniting with a close friend after several years and suddenly she's got these pictures everywhere.
If instead the character with the horrible pastime is male, the hobby has to be more attached to his ego; for example, a misshapen wood piece sitting uneven on a severely dinged desk with blueprints to a majestic birdhouse, but he's made so much progress he doesn't see how far away he is and instead he's become very proud of his work and is showing it off to a buddy or a would-be girlfriend. Instead, they're taken aback and can't say anything but smile and nod and ask for the bathroom, where they go stare at themselves in the mirror and thought-narrate their next move. "If I tell him, he'll be really hurt/angry at me and won't talk to me for at least 2 days and I have that thing tomorrow I need his help for. But if I don't tell him, he'll keep showing it to people..."
These are more realistic than "Oh, you paint? These are really good!" and "Oh wow, and it has hinges and everything! Where did you learn to do that? You taught yourself?" As if everyone goes around teaching themselves how to whittle.