Imagine this situation.
You're in a night club and dancing on dance floor filled with lots of chicks. Everybody is dancing, it's very noisy and light is going on and off.
There is two points here.

1- All of women are dancing toward the DJ, meaning they are looking at DJ's direction, therefor there is very little possibility to catch any eye contact.

2- Most of women are in a group of two or more. They are busy dancing and having fun already. Therefor, again there is even less possibility to catch eye contact, and harder to approach and take her away from the group.

So, what are you gonna do here? How are you gonna approach them and make them dance with you and probably escalate things?
Consider two possibility.
1- You can not catch any eye contact at all
OR
2- You can catch very few moments of eye contact. Mostly without any smile or something.

Thank you very much beforehand.

Anybody?

And that is why you have to open sets.

Dance game is the hardest in my opinion and I won't lie.
I usually go in with a loud voice to girls sitting or the ones standing (before they start dancing). I open them, talk a bit, escalate with touching and finally start dirty dancing when I can move her.

The idea of going on the dance floor and just dancing freaks me out, it makes me look like a weirdo who's dying to get someone to be with him. Unless I'm with my friends, that's a different story.