Indeed; reference counting was one of the most important aspects of Objective-C. Probably the most difficult aspect of it was that while most of the time method

Indeed; reference counting was one of the most important aspects of Objective-C. Probably the most difficult aspect of it was that while most of the time method names have hints as to what increased a reference count, it wasn’t always obvious. And then, of course, you had Core Foundation functions which could be tricky to grok in terms of memory.