Why is it so hard for people to decide and make up their mind? what would you say is your reason?

i walk into petsmart i see people looking at cats, dogs, and fish. I walk into the shopping centers and into stores you can tell they want it but they cant make up their mind about getting whatever it is their looking at. Is it money, is it they must ask their spouse first, what is it? What is so hard about making a decision weather to do this or that? or get this or that?Why is it so hard for people to decide and make up their mind? what would you say is your reason?
I have never can make a decision when it is going to affect other people because I have social anxiety and so I am afraid I will make the other people mad at me or something for the decision I made.