also is there any way to make sure my dwarves dont keep making useless crap like that?
Moody dwarfs make artefacts according to their highest appropriate skills.
Masons make rock furniture, carpenters make wood furniture, weaponsmiths make weapons, bone carvers make bone items, etc.
Farmers, peasants, etc with some level of masonry will make masonry items, etc. Farmers, peasants, etc without any of the above skills will make craft items (and gain craft skill as a result).
What item they actually make is random, unless they "like" a particular item. A mason that likes tables will make an artefact rock table. A bonecarver that likes crossbows will make a crossbow. But a mason that likes crossbows will just make a random rock furniture.
Wetal workers sometimes insist on using their favourite metal (or at least they did in earlier versions), but material preferences don't seem to matter for other labors.
If you are willing to do a lot of micromanagement (inspecting all migrants for skills and preferences, and retraining them as necessary) you can get reasonable control over the sort of artefacts your dwarfs make. If a dwarf likes shields, train them in armourshithing, carpentry, or leatherworking and if they get a mood you will get a metal, wood, or leather shield. If a dwarf likes platinum and warhammers, make them a weaponsmith and if you are lucky you might get a platinum warhammer. (Conversely, if they like tin and swords, don't make them a weaponsmith, or you could endup with a tin sword).