That zoom on iPhone is a perfect Apple thing: here is a very useful feature, we will document it but never bother to publicize it, and it’s going to be buried behind a strange gesture requiring both hands (double-tap and hold with three fingers, then slide up or down!).

I can’t change the behaviors of others. And, in practice, while email isn’t really considered a conversation, messaging is. Stuff that would be no problem in a physical conversation (three people laugh) is incredibly distracting when every one of them feels compelled to note they found it funny.