I go through a rigorous pre-dive check and plan. If they stay interested, I'll dive with them. I usually offer a friendly tort along the lines of "Don't make me punch you for being one of those clowns that don't pay attention to your surroundings. Oh, and if you catch me being stupid feel free to call the dive." Then there is laughing and a "No worries" retort and we dive. If something goes wrong we chat. If they are not concerned, I become a bit confrontational. I have a wife to go home to and I will not let someone keep me from her by being unconcerned with a problem. If the problem was low key...we debrief and move on. I do not want to fight, I just want to dive safely and try to keep my buddy safe too. I am not afraid of looking like a dick for the sake of safety.