Discussions about diving are very often boring—always the same stories about numerous sharks dangerously close, strong current ripping a mask off or friendly dolphins playing during a deco stop. We heard them so many times.
So, if you want to have some fun, simply say that you dive on your own with a rebreather and wait for the reactions. You’ll hear some nasty comments about you being an accident waiting to happen, and some people will clearly show you their option about your mental health.