I have said before in past posts - I think a belief in a god is because of two bad reasons.
1. Ignorance (not always deliberate at all) of certain facts. i.e. the Universe and life on Earth was not designed.
2. Wanting to believe in a god.
So, to focus on the second, I can see why people would want there to be a god.
You see dead loved ones again, you live forever, you have a purpose set out for you, you feel there's always a being with you through even your most difficult times. For those who believe in a god, could you live without one? Would it make any difference? Would you feel your life was still worth anything?