Is it zoom recommended/good on Digital Photography?

I just bought a Nikon D3100 and I have been practicing photography because I like it, I have been taking photos on manual too to practice the aperture, shutter speed and and the ISO, and I tend to use zoom a lot because I think the object/person sees more focused because of the blurry backgound.

Is it recommended to use zoom or to get closer to the person/object I'm shooting?

P.S. I have a 18-55mm lens.

Each shot is different.

Sometimes I'm within reach of the dragster I'm shooting and using a wide angle lens, other times, I'm 60 feet away, so I use my lens zoomed to 70 mm.

You have to learn this by practice and experience.

What is most important is that you compose your shots well and get near perfect exposures