As someone commented on this thread (and possibly others), the final stage of refining an item is rather frustrating. Once it’s free, you are mindlessly clicky-clicky-clicking until you get the perk you want.
I think this would be a lot better if there was a drop-down list to choose the perk we want (as someone suggested on that post, but…). Initially the list would be empty, and every time we paid for the service a new random line would be added to it, so we could still choose between what we had before or what we just rolled. Once we reach the point where re-rolling becomes free, the list would get populated with all the missing items, giving us full freedom.
This would not only be less frustrating, but would also incentivise using the service more, since you don’t have to worry about rolling something worse than you already had. It would also make it easier and more fun to try new things out.