I do not know whether to laugh or cry on this silly question. In fact,marrying your best friend save you all the bothefation you have to face for cultivating the stranger by your side. With a friend you already know his/her plus/minus points and that you have continued to be friends with him/her despite all that eases your post marital burden of tension fearing at every step whether the next step would land you in a pit.If it is pit you are sure he/she will also go along with you or pull you /him/her out.It is always better to have a devil you know than a stranger.