Fictitious person description

Well, let's imagine that I have a fictitious friend called... Robin, for instance. As long as he's imaginary, he has to be ideal. So, firstly, Rob is rational, sensible, friendly and sociable. We always understand each other and always have something to talk about. Rob is a reliable guy, he hasn't ever said anything to someone (except myself, of course). So, I can easily share my secrets with him. As my friend, he just has to be witty, and he is. He laughs at my every joke! What an amazing friend! Finally for positive points, he diligently tries to be punctual, and he is doing that quite well so far. As for drawbacks (just as for any person), Rob is so much garrulous so that it's sometimes difficult make him stop distracting me. Also he's a little independent. Why is this a disadvantage? Because when Rob feels he's fully independent and free, he will live separately from my mind and leave me alone :(