I was a nanny for years, live in and out, and babysat for many many families so I feel like I've seen all the things listed here! So many houses don't have bathroom bins, this is my workplace! If it was an office or other workplace it'd be terrible not to have a bin, but houses it's ok. I got used to always having spare nappy bags in a waterproof pouch in my bag, wrap up sanitary items and take.
My biggest peeve was living in and the bathroom had a shower head but no hook for it on the wall. Three houses I've worked in had this, you wouldn't think so but apparently common! So you had to hold the shower head over your head, and either lay it on the floor and hope it didn't turn over or spray everywhere while freezing to death trying to shampoo and wash, grab it with soapy hands and try to rinse one handed. Just an utter pain. One of these had no shower curtain too so you'd spray the whole room.
Carpets in loos and also really noisy fans coming on when you turn the light on, horrendous when staying somewhere and either waking everyone up or peeing with the door open to see. My current flat has this, I hear the fan going on in the flat downstairs at night so I know they hear mine.
Boiling water taps! Great idea, very expensive, very spluttery and feels like a danger to run boiling water.
I'll admit I must be an annoying host, I rarely drink hot drinks or use milk for anything so never think to offer teas or coffees, or have any milk to add. I had someone in ages ago to sort the washer and he asked for a cuppa and all I could offer was liquorice tea or a sachet of hot chocolate.
I also find it really hard in a house where the tv in on all the time, I don't know how people can have it on in the background and not just constantly watch. I find myself asking people to repeat something as my concentration is split. My downstairs neighbour has tv on all the time, all day all night, I hear it all day in the living room and all night in my room. It drives me mad and I'm a flat away!