Before he turned four, he:

visited Yeosu World Expo

watched an F1 race, pro soccer and pro baseball.

gave up (forgot about) his blankey

quit diapers and used the toilet

learned to choose his clothes and get dressed in the morning

he can work buttons and zippers

helped wash the dishes

consistently does his chores

traveled to Canada, the US and South Korea

practiced riding without training wheels

earned his yellow belt and green belt in taekwondo

got his first stitches

went fishing

learned to ride city buses, taxis and trains

(Good job, son.)