I'm oddly good at building attraction and being naturally confident and funny/cocky at my workplace, actually at every job I've had, with my female coworkers.

But when it comes to nightclubs or parties, my game dies down just a little, not so much though.

And at public places like school, stores, libraries, I'm just god awful at approaching and building attraction.

Why is that? How to fix?

I think its a confidence issue. At work, you know what needs to get done, and you can probably do it with no problem. You aren't worried about the tasks at hand and feel confident about what you are doing. This is an attractive quality for women, and since you feel comfortable at work, its easy for you to hit on girls.

Out in public, it can be a different situation every place you go. So if you are not confident in what you are doing, then this lack of confidence may rub off on girls and become a turn off. Also, you would be more worried about what you need to be doing instead of being comfortable, which is why you find it hard to flirt or make connections with success.

My advice would be to start having confidence in yourself regardless of where you are. Find that mindset you walk into work with and look at how you feel, how you carry yourself and how you interact with people around you, and apply this to every aspect of your life.