Implementation Inheritance Considered Harmful?

As the years go by and I see more and more painful bugs and convoluted architectures in OOP systems the more convinced I am that implementation inheritance is almost always the wrong answer, and that some kind of trait/mixin/delegation system is superior. Inheritance sucks partly because you’re expected to extend a class that you didn’t write (or that you at least ostensibly plan to modify independently), by patching into a few of the methods here and there and mucking around with the “protected” innards.