Because you like The Genie in Aladdin
Howard Wolowitz is an engineer whose serious mommy issues somehow haven't dimmed his confidence. See them in The Big Bang Theory.
If it were up to her, Merida would spend her days practicing archery and swordfighting, riding her horse, and exploring the Highlands. See them in Brave.
Shuri is a genius-level inventor with a wicked sense of humor. See them in Marvel Cinematic Universe.
A meek schoolteacher, Mary Margaret Blanchard can't remember her past as a spirited, swashbuckling Snow White. See them in Once Upon a Time.
Topanga Lawrence has been a put-together intellectual since basically the moment she could talk. See them in Boy Meets World.
Hank McCoy is a quintessential nerdy scientist but with a few rather unconventional physical attributes. See them in X-Men Series.
This cannibalistic villain may be a loner, but Killer Croc doesn't have problems with self-confidence. See them in Suicide Squad.
His name is Inigo Montoya and whoever killed his father should be prepared to die. See them in The Princess Bride.
The Grinch's heart is just too small to appreciate Christmas. See them in Dr. Seuss' How the Grinch Stole Christmas.