Upon entering a gym for the first time, you are forced to join a team before moving on. That's because when you're battling another gym, you do so on behalf of your team. No Pokémon trainer is an island, not in Pokémon Go.
Candela is the head of the red team, and she's got spunk for days. Her M.O. is very much in line with what Pokémon trainers have been taught from the get-go: To be the very best Pokémon master, you've got to train for it. Bonding with your Pokémon helps to tap into their strengths, according to Team Valor. If that sounds good to you, go Valor. Also, if you like the fire bird legendary Moltres, that's another reason to go with Valor; Moltres is its mascot.
Spark is the leader of Team Instinct, the yellow team. Spark is all about trusting your instincts — hence the name of the team. (Spark is not one for nuance.) If you feel that Pokémon are innately talented, and that success in battle can be chalked up to trusting your gut, Instinct is probably the way to go. Team Instinct's mascot is the legendary bird Zapdos.
Blanche is in charge of Team Mystic, the brainiest of the bunch. The blue team is most interested in evolution; beyond that, the members of this faction are cool to a point of intimidation. If you're interested in the science behind what makes Pokémon tick — and are convinced that keeping calm is all it takes for success — choose Team Mystic. Mystic is represented by Articuno, the icy legendary bird.