How often does someone think long and hard about A vs. B, pick one, and then regret it later? Sure it might have been the sub-optimal choice in hindsight, but we're not clairvoyant and often try to be thoughtful in our decision making. Can you really regret such choices?

Then there are those activities that we didn't do and didn't even consider. Not spending time with family before it's too late, not finishing a big project due to laziness, etc. These I'm more prone to regret.