Rainbow Dash

In Friendship is Magic, part 2, Nightmare Moon tests Rainbow Dash's loyalty by creating an illusion of an elite flying team called the Shadowbolts. The Shadowbolts offer Rainbow Dash a position among them, provided that she abandons her friends and their quest to find the Elements of Harmony. Rainbow Dash chooses to stay with her friends. When they confront Nightmare Moon in the Castle of the Two Sisters, Twilight Sparkle declares that Rainbow Dash represents the element of loyalty.

Rainbow Dash's loyalty is tested in The Return of Harmony Part 1. Discord shows Rainbow Dash a vision of Cloudsdale falling apart in her absence, convincing her to abandon her friends in the Canterlot castle maze.

In Rainbow Falls, Rainbow Dash faces a choice between flying with the prestigious Wonderbolts and the Ponyville team at the Equestria Games' flying relay competition. She secretly practices with the Wonderbolts at first but ultimately decides to stay with the Ponyville team.

In The Cutie Re-Mark - Part 2, in an alternate-timeline Equestria ruled by Nightmare Moon, Rainbow Dash is one of her loyal royal guards. She demands that Twilight give Nightmare Moon the information that she wants to know.

Rainbow Dash describes her passion for winning in a flashback in The Cutie Mark Chronicles. She races several times with Gilda, her old friend from Junior Speedster flight camp, in Griffon the Brush Off.

In Fall Weather Friends, Rainbow Dash loses a game of horseshoes to Applejack, and says she hates losing. She then challenges Applejack in the Iron Pony competition. In several rounds, she uses her wings to give herself an unfair advantage. During the Running of the Leaves, Rainbow Dash continues to use underhand tactics even though her wings are tied down. Applejack retaliates with tricks of her own, and both end up tying for last place. They realize that their competitive streaks got the better of them, and apologize to each other and Princess Celestia before amicably running the race again. Despite this, she and Applejack fall back into being overly-competitive with each other many times more over the course of the series.

In Rainbow Falls, Rainbow Dash comes to the conclusion that even though she loves winning, she loves her friends "waaaaay more."

Rainbow Dash displays confidence in herself and her physical abilities in multiple episodes. In Boast Busters, when Applejack and Rarity criticize Trixie for showing off magic tricks and looking down on other ponies, Rainbow Dash adds, "Especially when ya got me around being better than the rest of us."

In Sonic Rainboom, Rainbow Dash is confident about her performance in the upcoming Best Young Flyer Competition until Rarity's magical butterfly wings get a lot of attention and admiration. Despite her insecurities, Rainbow Dash successfully pulls off the sonic rainboom and wins the competition.

In The Mysterious Mare Do Well, Rainbow Dash is venerated by Ponyville after performing heroic deeds around town, one of which being saving Aura from a deserted well. She basks in the attention of the townsfolk and her official fan club (led by Scootaloo) and becomes over-confident in herself. A mysterious cloaked pony starts one-upping Rainbow Dash's feats. Rainbow Dash eventually finds out that the cloaked pony was actually her friends in disguise, teaching her a lesson about keeping her pride in check.

Rainbow Dash and Applejack snicker at Twilight Sparkle for running a race with them in Fall Weather Friends, calling her an "egghead" for joining a race with no prior running experience except reading a book on the topic.

Upon seeing Rarity wear a scarf for a mountain expedition in Dragonshy, Rainbow Dash sarcastically says, "That'll keep you nice and cozy." Later in the episode, Rainbow Dash expresses her annoyance and frustration when Fluttershy panics over minor obstacles in the trail.

Rainbow Dash begrudgingly lets Rarity give her a makeover in Swarm of the Century with a frown on her face. When Twilight Sparkle tries to convince Rarity that she's not a laughing stock in Suited For Success, Rainbow Dash bluntly says, "She kind of is."

Rainbow Dash's bluntness isn't always called for, though. She calls a dragon lame after seeing it do a trick in Dragon Quest, but then gets her coat singed after nearly getting burnt by another dragon's fire breath. She also teases Spike about his maid outfit in the same episode before being scolded by Rarity.