Aristotle put it as "Masculine republics give way to feminine democracies, feminine democracies give way to tyranny."

Basically people don't like it. Usually voters are almost a minority. Non voters tell you their vote will change nothing. And then all complain.

"Have you met Chris Martinez?"

Politicians.

the possibility of mob rule - what's popular is not necessarily what's right

Don't know. Never experienced ancient greek democracy.

America!

...some people are dummies, anarchists, selfish and will complain regardless of the choice. Your chosen to be a leader - so lead.

It simply doesn't work (which already is a bad argument by itself)

Too much stands in the way of actually getting things done, and there's too much corruption. Or another possible argument: the average person is way too stupid, uninformed, and easily swayed by frivolous things to know what's best for them, or at least what's best for the state/everyone.