"I don't need to practice that. I'm good."
I can't tell you how many times I've heard a client say that as we are preparing for an important interview. If it has been a while since we did our last mock interview I have to challenge the statement, especially when I know their personality trends toward being overly confident.
"Great. But just to be sure let's hit the opening statement just once," I say. "So, tell me about yourself."
If they can't go straight into it from muscle memory and nail it then they haven't practiced it much at all. Most of the time they fumble around and forget key parts of it. Then the excuses begin.
"Well, you caught me off guard. I'll be much more prepared tomorrow." Perhaps. But only because we just uncovered that he wasn't really prepared at all.
Confidence is a great thing. It can certainly help win job offers. But, over confidence leads to losing jobs you should have won. You came into the final round as the front runner thinking, "I got this." But after the dust settles it's devastating when you learn, "I don't got this."
Even if you have mastered a skill it takes a lot of practice to maintain it. Put in the work and play all the way through the whistle.