I think many are upset about the mail in ballot because uninformed voters who usually don't bother to vote because they don't know anything about politics and economics just asked their friend : who do you vote for? And then voted without knowing what they voted for. Which isn't cheating, but it certainly reinforce the strengh of propaganda in pushing one candidate above the other from the media.

As for me, I'm canadian so it affect me differently. Biden is good for the stock market. I think he's awful for the american people, but for foreign investors like me, he's great. Even in Canada we have more strict elections (everyone need voter ID) and we don't use machine to count votes.