I will write the following as if I know what I am talking about, feel free to correct me :) Okay, so we have theorized (using general relativity) that the force of gravity is in fact a fictitious force, resulting from observing motion in a curved spacetime. It is therefore unlike the other forces, which are considered to be real in the sense that they are not illusions resulting from poor observation. Also, gravity is purely an attractive force, and therefore also fundamentally different to the other 3 forces. Why then do we think it uncomfortable that gravity is "10^-38 times weaker" than the strong force, or whatever the factor is (we all know it to be small)?? Is it not totally OK, since gravity isn't a force and we shouldn't be making this comparison? Or does this stem from the desire to have gravity, whatever it may be, being mediated by some force-carrying particle such as the graviton?? I don't understand really why it is considered a problem, but I have heard people talking about it. Would be nice if someone could explain the crux of the matter to me.