I friend who used to be a cleaner in a hotel admitted to me once that he would normally just wipe down the mugs and glasses with the wet cloth he used to clean the sink, shower etc… put me off ever using those mugs again without washing them myself first.
Couple of pet hates I have that others don’t seem to have mentioned yet:
Hotel reception staff who do paperwork or respond to emails instead of serving the enormous queue of people waiting to check in. If it is that important, why can’t they do it at a proper desk in an office somewhere, rather than the first thing you see upon arrival being someone completely ignoring all the guests.
Hotels who feel the need to fill large bedrooms with ridiculous amounts of furniture. On a recent trip to Dubai my room had a desk, dining table, dressing table, coffee table, two large bedside tables, and three other side tables. Add to that a sofa, seven chairs, and two floor lamps, it became impossible to move in the room without either tripping over or stubbing a toe on a piece of unnecessary furniture.
Airlines who wait until boarding, to inform you that because of a change of aircraft your assigned seat is no longer available. Despite the fact the different aircraft has been sat on the ground for a couple of hours, and was en-route for several hours prior to that, it isn’t until boarding time that any airport staff realise. Seats could have been reassigned at check-in, or while waiting in the lounge, or they could have called people to the gate early to reassign their seats. But no. Instead they change multiple boarding passes at the gate, delaying departure. Once onboard you find that everyone is trying to swap seats so they can sit with their family, because they were assigned new seats apart from each other, further delaying departure.