“My dad grew up in a very strict Roman Catholic family. His mom was from Italy, from a city near Rome, very strict. And so every good Friday from 12-3 (which is supposedly the time when Jesus was on the cross), she made my dad sit in his room and think about Jesus’ suffering. Until Jesus was ‘off the cross’ and he could come out of his room. But he spared me that. But apparently, she had done that—her mother had done that to her, her mother had done that to her, and so forth. Not praying, just thinking about Jesus’s suffering and sacrifice for three hours. It went way back.”
Good Friday is the day that, according to Christians, Jesus was crucified and thus made his sacrifice to save humanity. This ritual was presumably meant to focus devotion and think about what Jesus had done for mankind, to try and understand the value of his sacrifice. Rather than praying, which could easily just be beseeching at that age, this tradition could mean to honor the suffering and the actions of Jesus, hopefully inspiring piety and good behavior thanks to the contemplation of such immense suffering. It is significant that it was meant to occur at apparently the same time that Jesus was on the cross so many centuries ago; such a thing would make the exercise more meaningful (homeopathic magic), possibly inspiring the person who is thinking about the suffering to be as brave or as compassionate as Jesus.