Ugh, no! I'm already pissed at the 5 seconds wait, if they add this too I'm gonna rage quit

I see this as more of an accessibility feature than something that needs to be user-shop specific... I'm just not sure how that turns into implementing it.
A lot of phones with good accessibility suites (TouchWiz from Samsung comes to mind) have tons of little tweaks you can make for various conditions and preferences. Being an OS they're obviously more extensive than they would need to be for Subeta (for example, anyone who needs a screen reader probably doesn't need it just for Subeta) but I'm sure Subeta does/should work with them to be at least the minimum degree of compliant, at least when brought to their attention. Most of it is probably already part of web standards as a whole anyways.
This I see as being at least a little more Subeta specific... confirmation boxes everywhere for those who don't need/want them for sure aren't the answer. So far, confirmation boxes have mostly been applied in either the more damning places (abandoning a pet, for ex) or the more out-of-the-way.
Basically, it would be nice to be able to either turn on confirmation boxes everywhere, or to format some kind of 'different' click - long press is usually the ideal in mobile, but obviously doesn't work for desktop. Shift-click or similar could work, but requires more dexterity than many wanting this feature may have. I don't know what the ideal solution is, but offering something like one or more of those could be quite nice and inclusive. Probably more the first than the latter (since their may already be software/third party solutions for that) but the latter may be more doable.
That presumes either is even a remotely doable level of recoding though, and as such it's probably a much more long-term/'big picture' type thing for Subeta.
No way, it would be too annoying when questing. :X I've accidentally bought items before as well when the page scrolled while clicking. It sucks but you can always sell the item again.
I'd love this if it was for a specific amount of SP - like say 500k or 1mil+ I just accidentally misclicked and bought something for 15mil rip :'v
Yeah, that seems like a good idea. At that point that's way past how much a quest item would cost so for the most part the inconvenience factor is taken away.
And it's perhaps worth noting in many browsers if you click to open the link in a new tab (so middle-click, ctrl+click, etc) that will override a JS confirmation dialog. That's what I do in my inventory, for example, to avoid all of the confirmations.