Phineas and Ferb

Phineas Flynn and Ferb Fletcher are young boys from the Flynn-Fletcher family and the titular characters from the Disney series Phineas and Ferb. During summer vacation, the boys embark on a grand new project, which is usually unrealistic in scale given the protagonists' ages (and are sometimes physically impossible). This annoys their controlling older sister Candace, who frequently tries to reveal their shenanigans to her and Phineas' mother, Linda Flynn-Fletcher, and less frequently to Ferb's father, Lawrence Fletcher.

Overall

 * 1) They are known for being the most iconic Disney Channel/XD duo to exist.
 * 2) Their inventions are so amazing and creative.
 * 3) They will do anything to make this the best summer ever.
 * 4) Their designs are passable.
 * 5) They have awesome singing voices.
 * 6) They do perfect chemistry with their sister Candace and their pet platypus, Perry.

Phineas

 * 1) He is very optimistic and constantly looks on the bright side of things.
 * 2) He is very creative, imaginative and open-minded, believing that the world has infinite possibilities.
 * 3) Manages to raise the mood of any depressing moment.
 * 4) He is very intelligent and he is genuinely a good thinker, and this is proven by his many inventions, such as when him, Ferb and Baljeet all made the portal to Mars.
 * 5) He remains calm in any situation and is very slow to anger.
 * 6) He has genuine care for anyone around him and is not shown to retaliate or seek revenge for anything.
 * 7) He has dignity and is not afraid to yell when he needs to, such as when Candace refused to co-operate in a critical situation in "Phineas and Ferb Summer Belongs to You!"
 * 8) His chemistry with Isabella is very sweet and heartwarming to watch.

Ferb

 * 1) He speaks in the third person, which proves that action matters more to him than just words, and it works very well.
 * 2) He has great lines of dialogue, aside from usually being a silent boy.
 * 3) He comforts people who feel anything but happy, namely Isabella.
 * 4) He is always calm, no matter what.

Overall

 * 1) Questionable character design choices. Even the show they originate from what makes fun of them for it.

Phineas

 * 1) Sometimes oblivious to emotions, such as Isabella's giant crush on him.
 * 2) Sometimes too optimistic in dangerous situations, such as Candace's constant and obvious methods of busting him.
 * 3) He may yell in a situation where he needs to show more compassion. For example, at first it seems like he did not want to understand why Perry kept the agency a secret from him.
 * 4) Despite what overall WTAGDIA#1 said and being a nice change of pace, he has been harsh on Perry and Candace which was very out of character, even for him.
 * 5) When he found out Perry was a secret agent who fight Dr. Doofenshmirtz, not only did he got furious for not revealing his identity in front of them, but also furious at him for not trying to warn them about Doofenshmirtz's true colours in Phineas and Ferb The Movie: Across the 2nd Dimension.
 * 6) When Candace accidently switch the Marvel superheroes powers, he refused to let her help fix the machinery. Then, when she accidently turned Baljeet into a Hulk monster, He had the gall to revoked her S.H.E.D. card and kick her out. When Candace tried to apologize, he didn't even listen one bit from her in Phineas and Ferb: Mission Marvel.
 * 7) He can easily irritated at times.

Ferb

 * 1) In the Phineas and Ferb: Star Wars crossover special, Darth Ferb's plan is to turn his brother to the dark side was a bit overdone in the Star Wars universe, like Vader with Luke, or Kylo Ren with Rey.