From the very beginning of the show, the Blue Ranger, aka teenager Billy Cranston, was always the controversial choice. He was the nerdy one of the group, into tech and not very good at all at fighting, and many fans questioned why he was even in the team. But as the seasons and episodes rolled by, he proved his worth time and time again, inventing all kinds of gadgets for the team and even becoming a competent fighter.
Fun fact: the name of the character, Cranston, comes from actor Bryan Cranston from Breaking Bad. Apparently he provided the voiceovers for a bunch of the villain monsters in the early seasons, and the producers liked him so much they named the character after him. David Yost, who played the Blue Ranger, was one of the oldest actors in the group - 24 years old when he started.