Manny Heffley

Manny Heffley is Greg and Rodrick's baby brother, and a major character in the Diary of a Wimpy Kid franchise.

Why He Sucks

 * 1) Being the third and youngest child of the Heffley family, Manny's problem as a 3-5 year old baby is that he is severely spoiled and entitled. He also throws temper tantrums very easily. He even threw a temper tantrum in the middle of a religious Easter ceremony, embarrassing the entire family.
 * 2) In Cabin Fever, Manny was at his absolute worst, when he acts like a misunderstood baby who knocked the power out of the house, and left his family to nearly die just because no one taught him to tie his shoes.''' And he didn't get punished because he's a toddler. No matter how young the person is, near murder is a very bad thing and the perpetrator should receive punishment.
 * 3) *Additionally, he doesn't get his comeuppance, as on Christmas he get toys and a pair of shoes.
 * 4) *To make it worse, even though he was taught how to tie his shoes, he still had Susan tie his shoes for him.
 * 5) He embarrassed Greg on saying "bubby" during the rehearsal of Wizard of Oz at school, which was ruined because of him.
 * 6) He abused his intelligence when he hacked Greg's Net Kritterz account and changed the password.
 * 7) No one is brave enough to stand up to him. Not even Susan and Frank, and he doesn't get punished for his actions, making him a karma houdini.
 * 8) *As such, he uses his young age as an excuse to do bad things, which is why a lot of times he doesn't get punished for his actions. While it's understandable for him to do bad things given his age, it still does not excuse his behavior.
 * 9) He has no sense of boundaries, like wearing Greg's headgear, as shown in The Ugly Truth.
 * 10) He is a huge tattletale, as shown in Rodrick Rules and The Last Straw.
 * 11) He may be a baby, Manny holds ridiculously powerful grudges towards Greg, Rodrick, or Rowley.
 * 12) In Wrecking Ball, when Greg was going to do something, he wanted to come with him, Frank told him he was too young to help, so he had a temper tantrum because of that.
 * 13) He has a rather questionable design and looks like some kind of crocodile with two teeth rather than an actual baby with a circle head for example.

Redeeming Qualities

 * 1) "PLOOPY!"
 * 2) He sometimes doesn't bother his brothers, Greg and Rodrick.
 * 3) He means well since he's a toddler.
 * 4) Though Susan and Frank don't ground him, they have been shown sometimes to get angry at him and there have been some occasions in which they reprimand him for the troubles he causes (like when Susan convinced him to apologize to Greg for breaking his console in Rodrick Rules and Frank having to buy a leash for Manny because he was trying to escape from them to retrieve his pet pig in The Long Haul)
 * 5) Given his age, Manny still has time to change his baby-like behavior as he grows up.
 * 6) In The Deep End, he did fix the bridge by making the RV connect to it, which is decently nice of him.
 * 7) The Diary of a Wimpy Kid book series would most likely not be as good as it is without him.

Videos
https://www.youtube.com/watch?v=Yzz8g5ag0eY&t=281s