Why do so many people carry their feelings into business?

It's become a world where one person only wants to work wih someone he/she "likes". It's kind of terrible. People are very sensitive and bring those sensitivities into business. Is it that hard to leave your emotions aside and just do business for the SAKE of doing business? Even with someone you may not "like"? I know I can, but a lot of people cannot. It's terrible. Work is work. Business is business.