You fly through lime underground terrain, mining chlorophyte and life fruits, you don't own very powerful weapons, and enemies hit you very hard (even with melee setup) and are spawning very frequently, especially during blood moon. You keep taking tons of damage, clutching at less than 10-20 HP (regardless of having maxed out your HP or not), tired of being beating constantly, not close to covering most of your usable terrain with banners, and yet you don't stop and keep going with same gear without upgrading, being on an edge of surviving quite often. Why? Because you like it. Money and drops are worth the pain.