>>21
(Free) neutrons are unstable; they have a half life of ~886 seconds.
Gravity (when very strong) can send electrons into the nucleus. This is how neutron stars are formed.
>>15
There is also a sense in which the strong force is less comprehensible: it is strongly coupled, so perturbation theory fails. Little is known about QFT outside of perturbation theory, so we're basically screwed. There are attempts around this using large N approximations and lattice QCD (which basically amounts to brute forcing a path integral, if I understand it right). It is also strange because the color charges are non abelian, at least in the sense that they arise from a non abelian gauge.
Lastly, the weak and strong "forces" only operate at the quantum mechanical level, where forces cease to exist; forces are a purely classical concept. If you really wanted to, you could treat the standard model as a classical field, and get the strong/weak forces that way, but I don't think it would behave in a fashion that you might expect.