Newtonian physics has served us extremely well for a long time for big objects-heavenly bodies and gross mechanics. However, it did not deal with the extremely minute forces that are inside the atom.
If you think quantum theory is hard to understand, try the string theory. Or have a go at "A Brief History of Time" by Steven Hawkings. I have been over both of these more than once, but still have trouble understanding either. As far as telling someone else about them coherently, forget it.
Sometimes I think that a theory that is so hard to understand or to write about may not be correct. On the other hand, it may be that some minds are just too limited to be able to get it. Everyone is not equal-brain wise. And not equal in a lot of ways and no amount of human lawmaking will change that.