Do you count to ten before making an important business decision?

Actually, the question should have been, do you count to ten before making the final step in your business decision-making process? However, for obvious reasons, I had to adjust this question to fit the thread's title space.

I believe that there's no marketer who doesn't think twice before making an important business decision. However, in this particular case, I'm referring to those moments when you are about to press send for your offer email, or when you have to say yes/no, or when you are about to put your signature on some contract or something. The final step of the entire process that leads you to the point where you're making a change. Is it over already? Can you do something in these ten seconds to reverse it back, think it all over again, or maybe even change something?

My worst enemy in this case are the emails. I regret answering them with no second thoughts for countless times. I'm on my phone or I just got an important email in a bad moment. I can't help myself opening and checking it. Before I know it my answer is already on the way. After a couple of minutes or hours, I get an idea that the things could have been done differently. Luckily for me, those aren't life or death situations, but they influence my work and especially my relationship with the clients.

On the other hand, I like to believe that sometimes you need to act fast to grab an opportunity to do some work or win a client. If you are going to be a thinker and hesitate, then you are very likely that you're going to miss. Here I'm caught between these two scenarios. Sometimes is really hard to decide which one is best. Should you sleep on it or act now? Sometimes, counting to ten before doings something that can have important consequences really doesn't sound like a bad idea? Or, maybe this approach can soften you over time and you can use your business sharpness? It may sound ridiculous, but is it true? What do you think?