What are the best side activities in gta v story mode?

Based on the verified Wikipedia evidence, Grand Theft Auto V is a 2013 action-adventure game by Rockstar North set in fictional San Andreas with three protagonists. However, the provided evidence does not contain any details about side activities, missions, minigames, or optional content in the story mode. The evidence only covers the game's basic premise, protagonists, and open-world structure. Without additional sources containing specific information about side activities, I cannot provide recommendations for the best side activities in GTA V story mode.