Wearing silly hats at random moments is strange behaviour? I do that all the time. On the bus, slip on silly hat whilst bus driver is checking my fare. In the supermarket, slip on silly hat whilst the checkout operator is scanning my biscuits. In the pub, slip on silly hat whilst the barmaid has turned her back to get me a whisky.
The look on their faces when they glance back at me again? Priceless.