Source: Parmanand Jagnandan
At 4:20 in the video, my statement is not always correct. For an object on a level surface the mass may play play a roll in the friction, but if an object is on a vertical surface, then its mass may not play much of a roll. It is most correct to say that it is the smoothness of the surface and the NORMAL FORCE between the object and the surface, that causes a friction force to develop between an object and the surface. Sorry for the confusion.
Source: Parmanand Jagnandan