I dont do it for business suits. I dont have a problem with it done by others if the suit is nicely made. I would have a negative reaction to an obviously ready made suit that had had those added on as a feature  under the trying-way-too-hard category.

For odd jackets, it doesnt bother me as much because most men dont get odd jackets made and deshabille is more of an elegant comfortable look. Also for the sort of nightlife Hip style when it's more about money than pedigree, leaving a jacket button undone can be a part of the look.

If you want to impress your colleagues in the cancer research lab with your bespoke coats, Cruz, by undoing sleeve buttons, but don't want it to look intentional, keep the bottom-most button fastened but undo the second and/or third button(s).  This achieves the same desired effect, but makes it appear like you really accidentally left the buttons undone.  Now, I must return to my own work solving global warming.

I don't like it.

Especially egregious are those who leave two buttons undone.

I do it.

It's tacky, but I still do it.

Zara now makes their coats with the bottom cuff button sewn shut and flapping over the button to give the "one button undone effect" (wtf?), but I still do it.

I can't help it.

I still think it looks slick.