This is something I struggle with.
I know that physics originated from an experimental framework. We observe phenomena, then we try to come up with explanations for said phenomena, formulate hypothesis, then test them. That is fine.
But this breaks down when the 'fundamental forces' are involved. What _is_ a force? All the explanations I've ever seen (apart from gravity) seem to treat a 'force' as an atomic concept. They will describe what a force 'does', but not what it 'is'. Maybe that's something unknowable, but it bothers me.
F* magnets, how do they work.