Light novels are somewhat infamous for titles that are often ridiculous and/or ridiculously long, I'm looking at you WorldEnd: 終末なにしてますか？ 忙しいですか？ 救ってもらっていいですか？
Hepburn: Shūmatsu Nani Shitemasu ka? Isogashii Desu ka? Sukutte Moratte Ii Desu ka?
Translated as: What Do You Do at the End of the World? Are You Busy? Will You Save Us?
A lot of these series have an informal contraction which is used to refer to it without reading out the entire title e.g. the above is usually contracted to "SukaSuka". The contraction is taken from bits and pieces of the Japanese title, so, Shūmatsu Nani Shitemasu ka? Isogashii Desu ka? Sukutte Moratte Ii Desu ka? -> SukaSuka.
There are plenty of titles which have this approach, such as Konosuba: この素晴らしい世界に祝福を!
Hepburn: Kono Subarashii Sekai ni Shukufuku o!
Translated as: A blessing to this wonderful world!
The contraction is derived as: Kono Subarashii Sekai ni Shukufuku o! -> Konosuba
Some titles have a more offbeat approach such as Aobuta, 青春ブタ野郎はバニーガール先輩の夢を見ない
Hepburn: Seishun Buta Yarō wa Banīgāru Senpai no Yume o Minai
Translated as: Rascal Does Not Dream of Bunny Girl Senpai
Its contraction derives incompletely from: Seishun Buta Yarō wa Banīgāru Senpai no Yume o Minai -> buta. I understand this to be because 青春 has no equivalent in English but is often translated as "springtime of youth", the first kanji 青 is read sei as part of 青春 (seishun) but on its own can be read ao (as in the colour blue) which gives us Aobuta.
My question is about the origin of the contraction for Haganai, 僕は友達が少ない
Hepburn: Boku wa Tomodachi ga Sukunai
Translated as: I Have Few Friends
The part I can derive is: Boku wa Tomodachi ga Sukunai -> ganai. The hepburn lacks the ha kana and I don't think any of the kanji have an alternate reading as ha. Has it ever been stated how the name Haganai was derived?