When DP opens the second pack/bottle/jar of something, leaving half of a perfectly usable one open to go off, get spilled or otherwise get wasted. I've tried explaining that the idea is to wait until the one on the go right now runs out or goes off and then open a nice, clean fresh packet without having to go to the shops and possibly pay a higher price than the offers I usually buy things on, but the concept seemingly doesn't compute.
The one that annoyed me most recently was when I picked up the lightest carton of milk and innocently tipped it into my tea, only to find it consisted largely of bile and smegma. And there were no more teabags because he'd left half a box out when opening the next one and then spilled water over them. The cats didn't mind the three open cartons of cat food in the fridge though, as I just gave them the lot at once to get the stuff out of there.
Other things that annoy me are
Contact lens packets left on the sink/windowsill instead of in the bin that's directly underneath. Everything else is left clean, there are never bristles left in the sink, the soap is back in the soapdish, towels are never left on the floor and there's always a toilet roll on the holder and the inners put into recycling - but contact lens packets always get left out.
Finding damp things that have been left in the rarely used tumble dryer so they have to be washed again (and properly dried this time) upon discovery.
Why all my socks disappear in the wash into his stuff but never come back in pairs, only ever in singles.
Being told that all the washing up has been collected up and done, only to find five things in the spare room and at least one glass underneath the sofa at any given time. See also 'all the washing' excluding the stuff that really needs to be washed. Despite getting a dishwasher, I suspect this will still happen.
How any tool is instantly leaped upon and squirreled away in a drawer/under the bed/on the windowsill/a parallel dimension in the spare room where I can never find it, instead of going back in the toolbox and replaced in the tool cupboard. When I'm the person who does mechanical/technical/practical stuff here.
How you can never find a matching set of bra and knickers in the shops unless you need something like a 40GGGGGGGGGGGGGG bra and a size 2 arse. Even within ten minutes of the staff putting the new range out.
That every bloody dress in existence right now will either be in your size and the correct length but will only be ditzy florals, ruffled and frilled, leopard print and wholly unsuitable for work, but the things that are more sober and acceptable to your very formal employer are either a) not in stock ever, they just claim they exist or b) finish roughly 2cm below your arse cheeks.
Being a size 6 and a half on one foot and a size 6 and 3/7ths of a half on the other. But with a metatarsal width that means the only shoes that would fit are wide fit, meaning they turn into flippers.
Websites where you have to go into the Vendor preferences and individually reject cookies for over a hundred different companies because the site hasn't opted for a Reject All button and has set the default to On with the reasoning that people will give up after the first 125 individual gestures and allow them all that lovely, valuable data harvesting to sell on. side eyes MN