General cleaning of nitro vehicles is my r/c nemesis. Pretty much every other aspect is enjoyable to me, but I really hate removing spent castor goop and dirt. Electrics are much easier to clean. I love working on a well engineered vehicle, not so much the ones that require removing half the chassis to get at a differential, but even that's better than hosuework[. ]Paying for everything is a close second, as that is definitely a perennial thorn in my posterior.