Every electron in the universe is exactly identical to every other electron. It's not just that we can't tell them apart, nature itself can not tell the difference (this has observable consequences in physics). Not only that, the description of a positron moving forward in time is identical to the description of an electron moving backward in time.

This led Richard P. Feynman to suggest that there is only one electron in the universe moving back and forth in time, so the reason that all electrons are indistinguishable is that they are in fact all the same electron.

(I should note that Feynman did not mean this terribly seriously, but it illustrates as forcefully as anyone can that electrons are completely identical.)