What do I mean by "why big head" in Taiwanese?

For example, send a representative to do something,

In any unspecified way,

With the atmosphere, place, time and other convenient ways at that time,

For example, pick up five branches and give them to five people. The person who draws the shortest or longest branch is the representative.

Call this method a big lottery.

People who are drawn often say this sentence. Why me?

I hope I can help you. If you are satisfied, please accept it. thank you