Conny roofs...
especially the ones that are nearly perfectly flat and have no run-off,
or the ones that are really angled, but have a really narrow access down one side against the neighbours,
or the self cleaning glass ones where you have to use just pure and elbow grease,
or the the plastic ones where dirt has got between the two layers of plastic and you're not sure if it's there or not,
or any ones where the insides are so dirty, it wasn't really worth doing the outside anyway,
or wooden ones,
or the ones where little bits just keep on bleeding out of the framework,
or the ones where, when you're up a ladder, there is something right behind you, so you've got no free elbow or arm movement,
or the ones where the custy is sitting inside having their lunch and watching you,
or the ones with an apex roof that leans back against the house, with a box gutter,
or the ones where that stupid strip of facia plastic, just above the gutter line, keeps coming off and you have to keep pushing it back on,
or the ones right under large trees,
ones under small trees,
and don't get me started on pine needles.
So basically all conny roofs!