I'm a PhD student in the US. During my PhD I gave many conference talks, seminars, and presentations at our group meetings. In my talks, I often mention a creative way to phrase a problem, sometimes in a form of a scientific joke, sometimes as an interesting metaphor. These are always inventions of my creative insights that I had while preparing the talk/slides.
A couple of times I later caught my supervisor using the same creative ways of phrasing the problem in his talks. He applies this in places where he talks about the same or a slightly different problem. This happened in at least two of his keynote talks (where I was present in the room) and one lecture from a course he was teaching that I happened to hear a recording of later on.
I can understand his motivation as it might be the same as my motivation. When I do that, my main goal is to help the audience remember an important message from my talk, but it's also to entertain the audience (there's many boring talks already!), or challenge the audience to think differently about a problem. It's likely that his motivation is the same.
Nevertheless, this really bothers me. I can't make up my mind though if I'm right to be bothered by this. Does my supervisor do something that isn't "right" here? I never heard him mention that this way of phrasing the problem or this joke or metaphor comes from me. If he at least said something like: "one of my students says here that ______", I would feel okay with this.
Should I be open and tell my supervisor that this bothers me? I realize that (unless there is some form of misconduct, like IP breach, here) he might think it's a foolish thing to be bothered about. And I'm open to the possibility that he might be right thinking so. If I'm exaggerating, what is a more healthy way for me to look at this issue?