Answer:
I can wave my hands at you but I never say goodbye. You are always cool when with me even more so when I am high!
Two in a whole and four in a pair. Six in a trio you see. Eight's a quartet but what you must get is the name that fits just one of me.
I am a mountain at night meadow at day
If you lose one of me, you are upset, bewildered, and perplexed. If you lose two of me, you are blissfully unaware. What am I?
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I've told you all, I cannot tell you more. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.