Spills are always easier to deal with if you can get to them quickly. My sister was visiting me once and spilt her coffee on my pale green carpet She put a foot stool over the stain so I didn't see it until she had gone home. I wouldn't have been annoyed had she told me at once, as accidents do happen, but I did wish she had been upfront about it. Another time, she turned on my washing machine whilst I was out at work, and I had put a red dress in, waiting for washing. My sister did not check and I ended up with a full load of pink whites. Even then, I would not have minded, but she took the offending (very expensive and ruined dres, which had a big white collar) and shoved it behind the cistern in the airing cupboard. I normally overlook anything she does, on the grounds that she is a bit 'scatty', but I did ask her why she did that, and she said because she thought I would be angry. I found it quite hard to make her see that concealing it was far more likely to make me annoyed (I don't get angry, it is usually a waste of emotional capital). She also defended herself on the grounds that she kept her dirty washing in a laundry basket, not in the machine, so she didn't think to check.
It was a very small kitchen, with no room for a laundry basket, but I would have had the common (uncommon?) sense to check whenever I was going to use a washing machine.
The ironic thing is that she told me exactly the same kind of thing about our mother, who had broken one of her ornaments and hid the pieces!