Why are we doing the dares?

I’m planning on asking for a free coffee at a coffee house. If the person we are asking asks us “why are you doing this”, is the reason/answer: a) because its a dare, b) because I want what I want c) why not? d) whatever I feel like making up in the moment? Another words, are we to explain why we are asking? I’m noticing that I am wanting to justify why I’m asking–is there something to be learned from that?