Suicide in Serial Experiments Lain
Suicide is a common occurrence in Lain's world. The first suicide the viewer sees is the death of Yomoda Chisa by jumping from a building at the very beginning of Layer 01. The most common reason for doing so is to "abandon the flesh" and pursue an existence on the Wired alone.
It is debatable whether Lain herself can be considered to have committed suicide at the end of the anime. She erases her own existence, including her past, in order to fix all the damage she has dealt to the world, but she still clearly exists in the Wired and, at one point, manifests in front of a grown-up Alice.
In the game, Lain commits suicide by shooting herself through her mouth.
The concept of "abandoning the flesh" is popular in the Lain fandom and is something of a meme or inside joke between fans. On Mebious.co.uk, for example, people occasionally encourage each other to ascend to the upper level of reality, the Wired, and post about it after they have succeeded. A 2010 incident on Mebious involving an actual suicidal person led to controversy as while there were those who tried to talk the person out of commiting suicide, there were those who encouraged it. A year later, someone who claimed to be the original poster stated they were doing better and had entered therapy.