We Love to Be Surprised
Life can be kind of repetitive and boring. When something comes along to give you a nice little surprise, that can really brighten your day (even for only a moment). One of the reasons we play games sometimes is to escape, but if you couple that with the slot-machine style gameplay of microtransactions and loot boxes, it turns a simple multiplayer session into an adventure of not knowing what you're going to get next! That can not only be a fun distraction, but can become pretty damn addictive.