Such is the close relationship between Rob Smedley and Felipe Massa that the race engineer says there are times he wants to "punch him in the face."
Smedley and Massa first teamed up midway through the 2006 season and have one of the closest relationships in Formula One.
The duo have been through a lot together including a near miss in the 2008 World Championship and also Massa's horrific injury at the Hungarian Grand Prix a year later.
And it's the latter that the Brit rates as the worst day of his life.
"The low moment was when he was hit by a spring and he was almost killed - in fact that was a low point of my life," Smedley told the BBC.
The 39-year-old also spoke in general about his relationship with the Brazilian, who contested his last grand prix as a Ferrari driver in Brazil on Sunday.
"He is a great friend and like my little brother but sometimes like your little brother you want to punch him in the face three or four times," he added.
Although it has yet to be confirmed, many in the paddock believe Smedley will be following Massa to Williams next season.