THE 5TH WHEEL

Everybody knows who a third wheel is: it is somebody nobody wants to be. What I would like to pick on here, however, regards the number used in this expression, not its meaning. How many vehicles do you know of that have only two wheels apart from a relatively small number of carts, motorbikes and bikes? To the best of my knowledge there are four on most cars and so the third wheel is actually crucial for them to pull out rather than redundant, which reminds me English doesn't actually make sense. On the contrary, the Polish language adds two more wheels to this phrase, increasing its reasonableness. The fifth wheel, because this is what people say where I am to emphasize and visualize the unwelcome element, makes more sense, as four is the target number of wheels on the majority of vehicles and the fifth one is useless indeed. However, both the third and the fifth wheel could actually make the journey safer by chaperonage, paradoxically enough. And, to conclude, the fifth wheel is sometimes called a spare. What a gas.

Correction, that's a gas: above, the real-life six-wheeled fifth wheel.