One of the biggest giveaways of being in the presence of dedicated Doctor Who fan is that they constantly reference quotes from the show. It will soon become a natural and unavoidable part of the conversation and this cannot be easily prevented. For instance, if a Whovian and a non-Whovian spotted a statue in the street, the non-Whovian would simply pass it by without a second glance, while the Whovian would stop and mutter the immortal words "Don't blink!". It's better to be safe than sorry... right?