Once you put someone on ur mind u remember you have her one ur mind ur brain misses their face and for u ur missing that someone and because you seen their face and how they look you have gotten a picture of her or he in ur mind and you cant get it out thats why you miss they specific person
This missing is a yearning, longing to be with someone, to see them, of course you can long and yearn to see someone you have never met, someone you have a sense of, someone whose absence is felt even though you have never known their presence.