They are'nt really all that similar because Amity are peaceful people, while Abnegation are selfless. So, Amity leaders work for peace, while Abnegation leaders give to others. And your right, Duantless have to be selfless as well, as explained by Tris and Four in the first book. A lot of the factions are the same, sorta. But each of them is differnt. Dauntless are brave; Erudite are intelligent; Amity are peaceful; Candor are honest; and Abnegation are selfless. So there are reasons for all of the factions. And selfless are not slaves, just generous people.
I can see where this question is coming from, because the two A-factions are both about "other people." But the emphases are different. Amity wants everyone to get along; Abnegation wants to be a helper instead of a burden. So you could technically be a hermit and be in Abnegation (if they had hermits in Divergent); and you could be an entertainer and be in Amity. But I'd have a hard time seeing either of those in the opposite faction...say, an Abnegation leading a singalong or an Amity silently withdrawing so nobody thinks they're in the way. It just doesn't fit with the overall philosophy of those factions.
An Amity doesn't have to give to others. They could just politely say they won't. To them it is more important to make someone feel better on the inside than it is to do someone a practical favor, An Abnegation would do anything for you, but they could be acting...for the lack of a better expression, stiff the whole time.
Imagine asking peole for a favor. An Amity may refuse in a super kind way, and an Abnegation will do it, albeit possibly not making the most pleasant company. If you've ever met someone who agrees to help you acting friendly...I guess they are Divergent.
Hey, this is fun. This is why I like Psychology. I'd like more questions like this.
Abnegation are selfless to a fault, they think about helping others and not being a burden. Amity is about kindness, but it's more about forgiveness and peace. Abnegation is more about charity and work. Amity does do farming, but not out of a selfless need to help others but because they like farming and having fun. Abnegation could farm too out of selfless reasons, but they prefer actual change like running the government and other selfless work like driving public transport and trash pick up. They are humble whereas amity is boisterous and outgoing. Amity will through birthday parties but Abnegation would not. And Dauntless and Abnegation are similar in that they are both selfless... But it's more like the Hogwarts houses... Dauntless is Griffindor and Erudite is Ravenclaw/Slytherin, Amity is Hufflepuff and Abnegation doesn't quite fit.... perhaps they would fit in Griffindor or Hufflepuff... But not quite. Dauntless are brave and rambunctious, they help the socialist city of Chicago by being the military/police/firefighters etc., Amity are kid and peaceful and grow crops out in the big open places. Candor are lawyers and judges. Erudite a teacher's, scientists, doctors, engineers. Abnegation is the government and public transport and garbage cleanup, charity givers. Each faction plays a role that best suits the personality. The test tells you how your mind works and which faction you are best suited for. Divergent fit into too many categories... Aka normal people.
^Really good reasoning, kind of fits into what I wrote above...You explain these things very well and I enjoy thinking them throughI could even say factions' psychology is more interestign to me than the story itself.
So basically, Amity is "I want people to be happy about their lives and my company", Abengation is "I want people to achieve things in their lives and my company to help them do so".
Abnegation: Everything is a mess, I will help fix it even if it wears us all down, Amity: Everything is a mess, I will help people feel good even if it doesn't get solved, (THIS is why I don't believe any of the factions are really good for anything unless they are TOGETHER).