Because you like Princess Peach in Super Mario Bros.
Meat Boy tenaciously throws himself into danger, and when he fails, he immediately gets back up and tries again. See them in Super Meat Boy.
NiGHTS is a powerful but childlike spirit who hates being told what to do. See them in NiGHTS into Dreams.
Kind and friendly, Rinoa Heartilly is nonetheless an effective freedom fighter. See them in Final Fantasy Series.
When the safety of Hyrule is at stake, Princess Zelda does not hesitate to sacrifice herself for the good of the land. See them in The Legend of Zelda.
Juliet Starling is a cheerleader by day, gleefully unhinged zombie killer by night. See them in Lollipop Chainsaw.
M. Bison is a diabolical megalomaniac hell-bent on dominating the world. See them in Street Fighter.
Clank is the quintessential rational, intelligent robot sidekick. See them in Ratchet & Clank.
Crono may not talk, but this time-traveling hero's heart speaks volumes. See them in Chrono Trigger.
Ratchet is a shoot-first, ask-questions-later, and then-shoot-again kind of lombax. See them in Ratchet & Clank.
After figuring out how both the light and dark halves of his soul could co-exist, Jak is maturing into a real hero. See them in Jak and Daxter.
If anyone can stay optimistic and friendly under harsh alien rule, it's Alyx Vance. See them in Half-Life 2.