Out of interest do you not think it's strange that all protons are the same, all electrons etc etc. Is there literally 0 scope for them to be different? Or could there still room for their to be tiny differences between them that we just aren't currently aware of?

And do we ever find more exotic particles taking the same roll in a larger atom even if just for a brief period of time? I'm pretty sure I remember that you can add muons to certain things in place of electrons but this is all ages ago and it was never very deeply discussed.