I have come across distinction you can make in the language you use when coming to a decision, and it helps me illustrate a mindset that I try to follow to an extent.
"Making a decision" takes all responsibility for the consequences. You can make a decision about what food to have for dinner, or which movie to watch. It implies that you could have decided something else but chose not to. There was a delicate balance going on in your brain, but you decided to take the decision and the consequences that came with it.
"Coming to a conclusion" implies that you gave all thoughts a chance to settle. Once this is done, there is often no decision left to make. There is a right answer that you are destined to reach if you think about it enough. This is a good way to tackle really big problems like choosing a career or deciding whether to make a big purchase. As long as you don't rush the decision but mull it over carefully over a decent period of time, there will often be only one sensible option left. It also means that you should not regret the decision. The solution chose you more than you choosing the solution. Or that is how it feels. I hope that by doing this, I can be happier. After all, even if the decision turns out to be a bad one, it was obviously the correct decision based on what you knew at the time.
This all ties in very much ideas of free will and theories of consciousness that I have been reading about recently. After all, the second option does not seem to entail a conscious decision. But then perhaps even "making a decision" is a purely biological reaction of nerves sparking each other in sequence, and the outside influence of a conscience is an illusion. The study of consciousness makes fascinating reading, and I hope to write more on the subject in future.
I leave you with a question. Is it better to decide something quickly or to wait and be certain that your decision is correct? The former sounds best in many situations, but perhaps the latter will stop you from changing your mind... which could be the decisive factor