Moving Stuff

It's not every day you see a quotation from Groucho Marx on the side of a removal van - but there it was, large as life (and unattributed), in the space where you'd expect to find the company's slogan or statement of intent:
'Humour is reason gone mad.'
Not exactly a zinger by Groucho's standards, but it does have the distinguishing feature that it has nothing whatsoever to do with the business of moving people's furniture from place to place in a large van. Why was it there? I imagine the proprietor of the company was trying to demonstrate that he is that terrible thing so valued by the English - a 'character' - and that he has, what's worse, a 'sense of humour'. If removal companies must have slogans, they should follow the example of plain-speaking Kiwi Removals, whose vans bear the stark legend 'We move stuff'. It is sufficient to know that.