I just accidentally deleted a shared outfit that took me 4 hours or more to perfect. I was just about to put it on but deleted it instead! :/ Please add a confirmation pop-up so that this can be prevented! I know a lot of people don't like these, BUT it'd help to prevent any hard work from being deleted accidentally! :/

No Support. Yup, I don't like all the popup confirms, but it's also unnecessary.
There's tons of allowed Shared Outfits space, so there's no reason to not make eight or nine very close working-saves, it costs you nothing but the making of a temporary title like alpha/beta/gamma or firsttry/secondtry/thirdtry etc. so that you can tell them apart. This way it's only you who is inconvenienced by any tendency to misclick, and not everybody else. Once you've got the one you like and put it on and saved, you can then delete most of them and keep a few working copies to remember for later builds.
Nooo... Let's not.
I totally support a pop-up confirmation in this situation. Saying "just make 15 copies to be safe" is absolutely ridiculous for so many reasons.

yes. confirmation popup is always good and needed in a lot of area. yes people sometimes will still misclick them, but less people will. also there are options or addon in web browsers to disable popup windows if that seen as annoying.
If you're making users go out of their way to adopt odd behaviours to use a feature (i.e. making several outfit shares just in case they accidentally delete one) then it isn't designed well. I doubt it would be much hassle to add a confirmation!