system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] How do the Sith meditate?

I know Darth Vader would meditate while in his Bacta tank, and Sidious and Plagueis both used Force meditation to offset the need for sleep, but what are they actually doing there? Meditation calms you down, and that’s pretty against the Sith philosophy.
gpt
Sith meditate a little differently than Jedi. Generally there's two types of meditation: Mindfulness and Insight.

The goal of mindfulness is to focus on one thing and let it fill your mind, removing any and all distractions. This is a very simplistic summary, but it's enough to explain the differences. Jedi love this one (eg let the force move through you and whatnot).

The goal of insight is to reflect on your past and yourself, using it to help define your goals and shape who you are as a person. Again, simplistic, but helps illustrate the differences. Sith love insight meditation, instead of focusing on bettering themselves they focus on their hate.

Of course, both the Jedi and Sith can and do use both types, but their own variations to help connect them to their preferred connection to the Force. But they do generally have a preference.

Sith use their hatred to fuel and increase their connection to the dark side and insight meditation is a very useful tool in molding and reshaping your hatred and keeping you focused on your goal 

When Darth Vader is in the bacta, he's not clearing his mind, he's remembering the pain of betrayal from his order, the heat against his bare flesh as he lay dying on Mustafar, and the death of his wife and how powerless he was to stop it. He endlessly reignites his hatred for weakness and Jedi.