It's a terrible affliction, Tennant-itis. Once infected, the victim spends endless hours YouTubing fanvids and clips of the rude bits from Casanova, Blackpool and Secret Smile (a few minutes into the first 10 minute section, just for reference )
In advanced cases, the sufferer finds themselves trying not to be distracted by the expressive use he makes of his tongue, even, most worryingly, in Harry Potter.
Once set in, and very near the end, one may find oneself introducing an action figure of the Doctor as 'my boyfriend', and have a complete collection (Doctor (For every day), Doctor with coat on (For going out), Doctor with glasses (For intelligent conversation) and Doctor with Pentallian spacesuit (For when you want to ask him to take the rubbish out, like a proper boyfriend))
Research continues, but so far, the only remedy appears to be a short-term reprieve after watching 'Learners'. There is no cure.