It's just getting used to []][[][]] and having brackets and @property and lots of things a little different that most first languages people learn nowadays. If you're coming from C, then moving to Objective-C might feel different than coming from languages people tend to learn first nowadays. As someone coming from C++ (and others) when I started programming 4ish years ago, it definitely felt unnatural, but learned to appreciated it a lot and found it pretty sensible. Except for blocks...

It has made me really want to look into learning Smalltalk as a throwback hobby.