I like words that are several words shortened into one single word haha, like 깜놀 which means "what a surprise", or when you're shocked, and is a shortening of 깜짝 놀라다, and 엄친아 means mum's friend's son, meaning someone who's perfect, and it's a shortening of 엄마 친구 아들. I also like it when they say English words but in Korea, so konglish, like 레알 :D