要不然？

Did you guys ever think of the way we talk in our daily lives?

Just few examples for you;
Recall back! What was your first word when you bumped your old friends somewhere?

At restaurant :
Hi mate, coming for lunch?

At uni :
Ada kelas kah?

At basketball court :
打球哈？

What the fish?? This is common sense man.
I would answer you 要不然？！
Thank you.