If you want the photograph to look and feel good then there should not be any blur in your image. In order to make sure that you take blur-free images, you should know the factors that cause image blur.
Image blur is caused due to many reasons. Firstly, the shutter speed selection. If you are shooting with your camera hand-held then if you go for a slow shutter speed. This can result in an image blur. Secondly, if you are capturing the image at a higher F-number, without using a tripod then you may end up in a blurred image.