I think we know quite a bit. Maxwell's equations have unified electromagnetism. We actively exploit nuclear for energy (and deterrence of war, but I won't go th

I think we know quite a bit. Maxwell's equations have unified electromagnetism. We actively exploit nuclear for energy (and deterrence of war, but I won't go there) and armchair me thinks there shouldn't be a lot more to the strong and weak forces (~80% of it known?). What we don't have a good grip on is gravity and time at the ends of big and small (plank and galaxy) scales. And dark matter remains a giant mystery.