The best thing about bathrooms is that they are not a place where one stores memorabelia. Which means that they are easy to clean because one never has to make any decisions. You throw away the empty shampoo bottles, scrub the tile and the fixtures, wash the floor, and throw any dirty towels into the laundry. SO easy!
When I can't think of what to do, I sometimes clean a bathroom, mainly because I don't have to THINK.
Bathrooms also give you a lot of bang for your elbow grease. You can vacuum all day and at the end, things don't look very different (but your back might hurt). At the end of cleaning the bathroom, you have fresh scents and shining porcelain and mirrors. Plus, you know that you have just increased the hygiene level in your home.
I used to clean the kids' bathroom every night while they were bathing. I'd just sort of sponge everything down with water and a squirt of Windex here and there while they played in the tub. When they got old enough to require privacy, things changed. Now their bathroom gets filthy; I don't get in there very often, and they, apparently, did not register what I was doing all those years and continue it.