Maybe this is just me and my experiences but when I encounter people in the wild that seem dull I often assume they just have fringe interests that are kinda problematic to share with regular people they haven't built rapport with yet.
Like they're probably into something weird or niche that doesn't translate well in casual conversation so they just keep it surface level until they figure out if you're their type of person.
Like they're probably into something weird or niche that doesn't translate well in casual conversation so they just keep it surface level until they figure out if you're their type of person.