I never used to mind playful teasing and I can find it funny to bash on people, but I get nervous that sometimes it might be too easy to take it too far without knowing it and accidentally really hurt someones feelings. I have done this before, and had it done to me before, and even though we both knew it was a joke, it still stung more than it was intended. To me, it really isn't worth this risk, and so I don't usually play along with teasing anymore. I don't ever want to make someone feel bad about themselves, even if it might be accidentally. You can't always trust that people will tell you everything they might be insecure about.
I also grew up around someone like my father, who was basically always trying to act like a big brother by pushing me around by the shoulders and teasing me and constantly pointing out things I was doing and making me feel watched and judged all the time, so I might be a little ruined in that respect. He thinks he is just showing love, but your tactics need revising when it is clear the other person isn't enjoying themselves. Then it is just pure selfishness and bullying.