(The) people who had committed suicide (usually) had found their lives unbearable and too painful.
In what restaurant do you usually have breakfast? > ok > Type of restuarant , as in Japanese . Western, Indian, etc.
"In which" > the restuarent you normally go to.
Did you like riding (a) bike when you were a child? > Ok
Who else were riding in the car beside you? > Not good 1)" Who" is singular , therefore use "was" 2) "beside" means "next to/at the side of ..)
Who else was riding in the car besides you? > "besides"> "in addition to .."
Who else was with you in the car ?