The plot started weak and got steadily weaker and more cringe the longer it went on. Eventually it reached preachy and embarrassing.
Homer hating tipping has already been covered before, so the dumb 180 degree in the beginning made no sense. After that it just kept getting worse as we veered back into the boring cliche of Homer being too clueless to get how badly he was hurting everyone else. The delusions just kept getting worse until we reached the "socialst Europe good/dumb Americans bad" plot line that often pop up in weakest of the Simpsons episodes. It's often a sign that we're at the end of the season and the writers have run out of ideas so they're getting preachy. By far the worst episode since the end of last season.