You can also use that tactic (abandoning a quest only to pick it up again) if you're unhappy with a choice you've made or w/e, as it will reset your quest entirely and lets you start from the beginning again.
Just keep in mind if you complete the quest there is no way to go back for a different choice, reward, etc. but there is usually a clear "complete quest" dialog option that will give you a last chance to change your mind.
I don't always drink Skooma, but when I do I go to the Southwall Corner Club. May you walk on warm sands my friends.