Why is it Hard to Say Goodbye!!

There is always someone that tear your hearts apart that you are not gonna watch her face everyday.Why does it happen ? Is there any scientific explanation , I don't want to know because there are no solution.Life was good when you are not attached to someone but when somone just come to your life and show you how beautuiful the world and everything is. Then what happens , either they leave or me .I hate this nature thing , why doesn't it happen like we wanted to in a good way.I know now a days internet and everything people are so near but the thing is i want live, i want to hold hand , i want say her good morning and kiss on her cheek and make some stupid jokes to make her laugh to see her smiley face . I want this . I want to look into her eyes and i want to see those crystal eyes that looking into me and wanted to say something but she can't.Oh my god ! I can't say goodbye , it would just kill me .There is a burning rock attached to my heart -it feels like that.And everytime there is someone that make you feel no to go , but you also you don't have other option.After a while you forgot all of this feeling or it fades away until you meet someone again , and it goes again and again , well i don't know about other people but for me its like that way. I hope it doesn't happen again , Cause Goodbye  Sucks!