Go onto a liberal website, such as huffingtonpost, and suggest a world without taxes. It is not a concept that is even imaginable. Pretty ironic since these people like to think of themselves as "enlightened". They only see the side of what the government gives you. The concept of government taking is like a blind spot that they cannot fathom, it has been done that way for almost a century so there is no other option.
Give them a magical hypothetical where everything is already paid for, and unless people are insane, they would be happy not to pay taxes. Who the hell actually likes paying taxes? Nobody. Not even people like Warren Buffett who think their taxes should be higher in the world where we actually live.