Gravity - it's a real downer. It's a drag all the time. But it's fantastically weak. A small refrigerator magnet can hold up a paperclip against the gravitic pull of THE ENTIRE PLANET EARTH.
And nobody knows why. Why is gravity so weak? How weak is it? Gravity is about 10,000,000,000,000,000,000,000,000,000,000,000,000,000 (that's forty zeros, 10^40) times weaker than electromagnetism.
Please notice that that figure is in the same ballpark as the reduced Planck's constant (about 10^-34).
Please also notice that gravity, seemingly alone of all forces, actively operates in the realm of complex numbers. Imaginary space, direction, and energy. Which implies that space, itself, exists on the complex field, not just our real number plane. We just experience the real number portion of it. Maybe that's why we can't explain over 95% of the energy of the universe.
So, if gravity operates equally across all of quantised complex space, you would only expect something less than 10^-34 of that force to align exactly with the real number plane. It's simple probability. No extra, tiny, curled up dimensions required. Simply advanced math and a different perspective.
So, gravity is weak because it operates in complex space, in real-number space. We exist and interact solely with real number space and phenomena. Hence, gravity seems weak to us.
Corollary - What if 'dark matter' is really 'imaginary matter'? Matter existing off the real number plane of normal physics, and interacting solely along the imaginary plane? Imaginary space, direction, time and energy? That would make sense of dark energy, why it affects gravity (and our gravity affects it), and why it doesn't seem to interact at all with normal, real number, everyday existence.
Fun fact - when something falls into a black hole, it crosses over from the real number plane of physics to the complex field at the same moment it crosses the event horizon. Does the speed of light have any meaning in the complex plane? Or does it just apply here, in ordinary real-number space? Black holes aren't dissipating with any noticeable speed, so the vast majority of the energy must be retained. Dark matter seems to congregate around normal matter galaxies, so they are probably feeling the pull of black holes, too. But this isn't proof. Of course, by the nature of things we can probably never have real proof, but it's fun to think about.
I hereby label the positive imaginary axis of greater reality 'Heaven' and the negative axis 'Hell'. They are all around us, all the time. They're just set the width of one thought to the side, slightly out of phase with what we think of as reality.