Na Il deung was your Ex lover, He's easily jealous and is sometimes protective.

You were finding food at the Convenience store, you kept looking at shelves, finding what to buy, Then suddenly you bumped into someone he looked quite familiar.. When you realize he was your ex.

"Watch where you're going!!.." His glasses fell and he was trying to find it, he gave you a cold glare after he found his glasses on the floor, he then walked away angrily