Contrary to other definitions on urban dictionary, make sure you do NOT pronounce the "fan" element like a football fan. Instead it should sound more like "mah" "fahn"- the same fan sound as "fondue". In general usage it is roughly equivalent to the phrase "pain in the ass".
Also known to many as ma fan
2. Why did you give me all this shit to carry, you have no idea how mafan that is.
3. She is really hot, but she already has three kids, its too mafan to go after her.
Used by many foreigners in China, it expresses the feeling of chaotic despair, or an annoying situation.
Paul: It's... well, mafan. I don't think I'm going to get any sleep for the next 3 days, at least.
Julia: So what's happening between you and Fred?
Amy: Mafan! He never told me he had a girlfriend, and now SHE's hating on me like a mofo.