I think that as much as teams would like to think of their drivers as being ‘plug and play’ (you stick them in the car and they drive to the best of their ability) the fact is they are human beings and so are subject to all the variables that come with humans being diverse and different people.
Lewis Hamilton is a perfect example. Despite the fact that, in an ideal world, Hamilton’s personal life should have no effect at all on his performance in the car, his relationship troubles with Nicole Scherzerrrezzzezeerzeerszezeerzezzeerzzrrezinger in 2011 almost definitely contributed to him having his weakest season performance wise since he debuted in Formula One. Likewise with Felipe Massa, who is very much a confidence driver and had a very poor spell that could be traced back to Hockenheim 2010, when he was made to move over and give up the victory.
As much as McLaren want to be the ultimate professional and slick operation (although they have been trying to change their ‘robotic’ image recently), it’s far better to realise that you have to treat your drivers as individuals and nurture them into being at their best mentally, instead of treating them simply as tools for a job.