I wrote a bit of C recently, it's impressive how patternless it makes you think. At least not in the OOP way. You may think in patterns, but it's not encoded in source. It's implicit structure. It's also very different because every bit of help you allow in your source is carefully thought out, you want it to fit the fragile land of C and also now you're moving bytes somehow explicitely, you tend to think more about memory and cpu perf.. again less pattern envy.

ps: I also forgot to say, even though I'm a fp head these days, imperative C felt fun, that is if you carefully stay into state -> state mindset ;)