Nice user image. And we can talk about my paragraphs if you really want.

• Potentially, sure. Normalcy can mean happiness in some cases.
• Understanding isn't prerequisite, but pretty damn nice. I don't understand why WD-40 cleans oil-based paint off of your hands, but it's a hell of a lot better than trying to use water and soap. However, my misunderstanding is probably the root cause of some of the most uncomfortable parts of my life I can remember. For instance, I can never understand "dancing," because it isn't something that can (easily) be systemized or quantified, so I really can't enjoy it.
• Some systems my own, some pre-fabricated, I guess. Like wrapping my glasses around my alarm clock at night so I always know where they are in the morning, or designing a sensor and monitoring system to keep myself going on an exercise bike. Stuff to make things go more smoothly or efficiently, and to spend less time in tedium.

I probably don't understand the definition of existentialism, but if Wikiepedia tells me anything, I would probably agree that a person is responsible for their own meaning, and in the context of this post, their own happiness as well.