Are there any skincare recommendations that are a must-buy during the Olive Young sale?

It's Olive Young's sale season these days, so I've been browsing around, but there are so many different kinds that I'm having trouble deciding which one to choose.

Among the essences, creams, or mask packs that usually suit your soothing or moisturizing needs, is there a product you have personally tried that you were truly satisfied with?

If you have any recommendations you'd regret missing out on during this sale, or any great deals you bought with your own money, please feel free to share them in the comments!