I've had at least one coworker like this at previous jobs. They've tended to fool me repeatedly until I notice the pattern and revise my opinion of them. The co

I've had at least one coworker like this at previous jobs. They've tended to fool me repeatedly until I notice the pattern and revise my opinion of them. The confidence they display makes me think they're smarter / more informed / more thoughtful than I am, until enough evidence causes me to stop all positive weighting of their opinions. It's worse when you have imposter syndrome for the first several months of any new situation.