Ok, let me question and answer:
Aliens: We will nuke your planet
Human: err...bad idea. Why would you nuke a planet first and then live there. You are genius, and you should know that ecological system of any planet is the key essence of that planet.
Aliens: We will eat you.
Human: Why??? We are one of the most physically weak creatures on this planet. We also suffer from numerous diseases like heart attack, high cholesterol, obesity. Heck, we even suffer from STDs. Are you sure that you want to eat an ill spices? Why don't you try our cuisine like Italian, French, South Asian? N.B: Fish and Chips is not a cuisine :D
Aliens: We will make you our slaves
Humans: doh? You have advanced machinery and yet you want to enslave us? You do know that you'll need to feed us and take care of us. Also, we have a bad habit of turn into rebels. Are you sure you can afford it?
Aliens: We will abduct your women, and they shall carry our babies.
Humans: Please..by all means. You'll regret this decision. Dealing with a human female is more harder than approaching Pluto.
etc. etc..