The ultimate science bro.
Because he's got your back in every dimension and alternate universe.
Source: cognitionadrift.tumblr.com
Which he can easily travel through because he's a time lord.
Source: holdontothehopeofabettertomorrow.tumblr.com
Because you two have history.
Source: inktank.fi
Because he might be a bastion of science and civil liberties.
Source: ipromiseihavefriends.tumblr.com