Auto tree cutting.
Auto hair cutting/nail clipping. These waste products can then be used by spinners and bone carvers respectively. (Just imagine ... toe nail decorated marble mugs being sold world wide!)
Milkable beasts who are left unmilked for a lengthy time develop injuries.
Shearable beasts who are left unshorn for a lengthy time developed the 'fly struck' disease.
Give hunting dogs the ability to 'track' missing dwarves.
Enable worn out clothing to be used as rags to clean up spills more efficiently. (Do dwarves actually clean at all? Mine never seem to...)
Create a mop so as to clean up spills more efficiently. (To be used with buckets. And possibly soap. Also the laundry could use both buckets and soap too.)
Create a laundry industry to regularly wash clothing and rags. (No, dunking dwarves off a bridge doesn't count.)
Sometimes the heirloom created by a strange mood will be considered too abstract to be considered artistically of any value by the creator's peers, and lead to the dwarf being so overwhelmed by the criticism that they swear never to practise that particular craft ever again. This is reflected by a permanent ban on practising that skill for that dwarf.
So that I don't have to deal with the negativity of personally turning away every single monster slayer that petitions for acceptance and leave them to survive alone in the harsh outside world, an auto refuse option for all monster slayer petitions.
Dwarven gymnastics. Both a tavern spectacle, and a way to improve agility, dodging, kicking, discipline and jumping. Will need to create a leotard article of clothing.
Previous commenters 'terrible suggestions' that I actually like ... not just like, but think possibly should be implemented:
*Realistic lighting. It should be said there is the alternative viewpoint that dwarf's natural inclination is to live in, and see, the dark (a la the Discworld's dwarven religion), which leads to some additional things:
a) light sickness shouldn't just be vomiting, but also include some existential brooding on how the dwarf has lost their way in life after being blinded by the light, and if they can ever find their way back to the path of examining the depths of the souls again.
b) perhaps their ability to see in the dark comes from having some kind of phosphorescent/different spectrum eye sight (maybe heat radiation caused by magma bounces off different rock types at different frequencies ... yes I know what I just said a whole lot of rubbish), and they can possibly lose this ability due to either old age or poor diet, which, as with a) above, leads to brooding thoughts adding to stress.
*Uncleaned workshop areas can lead to bug infestations, which can degrade the workshops, depending on what they're built out of, and these infestations will attract various creatures to eat the bugs.
*Starving dwarves eat leather. Also ... starving dwarves who eat leather for too long develop hernia and/or IBS injuries. Also ... starving dwarves who are near death have a chance of developing a taste for dwarf flesh, or a reputation of having eaten dwarf flesh, which leads to them becoming a social pariah.
Oh woops. Didn't realise 'next' took me to the next post, not the next page. Soz.
*Fine Dining. Additionally : a restaurant location.
Side notes
re: the dentistry suggestion - did you know that in olden days when people went to the dentist to have their first one or two bad teeth removed sometimes people asked the dentist to just remove all their teeth in the one go so they wouldn't have to keep coming back again for further dentist appointments in future. They spent the rest of their lives using dentures. Could this be worked in DF somehow? Toe nail encrusted exceptional sheep wool dentures?
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Giant Cave Spiders are now eusocial, forming massive communal webs and working together to hunt down prey. They also reproduce like real spiders, with each female laying thousands of eggs per year.
That would be hella rad.
I utterly despise the pair of you. To oblivion. I'm staring at my screen right now intently wishing you both the worst torture imaginable. Coincidentally this happens to be stuck in a cavern surrounded by sociable pack hunting giant cave spiders.
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Okay, sorry but after reading that spider suggestion I can't read on any further past page 4. Need a little bit of a lie down. o/