Hey fellow Final Fantasy X explorer! When it comes to side quests, there are a few you definitely don’t want to miss.

1. **Monster Arena**: By capturing fiends from all over Spira, you can unlock challenging battles and earn some great rewards.

2. **Blitzball**: Don’t overlook this mini-game! Not only is it a fun way to take a break from your journey, but it also offers some fantastic rewards and unique items.

3. **Celestial Weapons**: Each character has a unique celestial weapon that is incredibly powerful. Be prepared to tackle tough challenges to unlock their full potential.

4. **Dark Aeons and Penance**: After completing the main story, test your skills against these super tough bosses for the ultimate challenge.

Make sure to explore every nook and cranny of Spira to discover all the hidden treasures and secrets! Happy adventuring!