Secret to Life: Consistency

I was doing some thinking about what makes a life "livable" - it's struck me, and has been constantly striking me since, that consistency is the mother of all virtues to have. Don't you think so?
When I say "livable", I mean organised, predictable and to a certain extent within control. Of course, we are never fully in control of our lives - many things often occur outside of our plans, unscheduled, unplanned and often unwanted - but those are common to all, and hence should not be considered here.

The existence of these uncontrollable items makes "consistency" even more important. Else, what would our lives be? Shambles? Messy events? A clump of activities without any explanation and not reproducible?

Reproducibility. I've always been intrigued by the notion. Do we always react the same way when the same input and stimuli are applied to us? This is common for machinery and software - but humans? Would this be a good trait or just plain boring? If a person kept acting the exact same way each time an event prompted him/her to - this person would be like a robot. However, that would be consistent I think. Also, reproducibility would also mean that we can explain our actions - why did we do this? It's because of this, this and that. Being able to explain our actions keeps us conscious of our decision making process. Instead of just "letting things happen" - we're very much in control.

What does this mean? Does this have a bearing on our lives? I think people with a certain discipline of consistency - breeding reproducible behavior that can be properly explained will live, over a long term, organised and happy lives. Of course, we all need spontaneity in our lives to keep things interesting - but too much of that and we might as well be mashed potatoes, or bouncing marbles rolling down a hill.