Earlygame is rather stale after playing it a few times. You know what you have to do and you wish you could do it faster.
As the scale expands after defeating one mechanical boss, partially due to the class system and the amount of things you can do becoming more and more, the game gets more interesting. "I don't want to defeat the Destroyer, let me make an Ankh Shield first. Now that I have my Optic Staff, I can traverse this world much safer", says the summoner, for example.
Things start to cool down after Pumpking though. With the material to finally take down Duke Fishron without risking too much, and the ability to get far enough into the Frost Moon event to grab their loot with a bit of luck, less and less things are there to do in the world. At least you can still resort to building, because Shroomite Digging Claws are beast.