I have an Interface Claustrophobia. Small or lack of spaces in the interface makes me anxious. Space sounds like a simple thing, but it can give a significant improvement to the experience, especially if we want to simplify the interface. People love simplicity, it makes their lives easier (or feels like it’s easier). The right space would help in organizing content. Second law of simplicity from John Maeda: “Organization makes a system of many appear fewer.” Adding more space would help you organizing content better.
See the comparison of Viki’s Android app below. The left one, although it’s working fine, but somehow looks cluttered. One of the reasons is the content hierarchy is not clear, the organization of the content is not clear. I simply add more space by changing the top margin of the section header from 18px to 48px, and it looks better. If you view the interface on your phone, the improvement is even more obvious.
So if you feel that somehow your interface looks cluttered, but you don’t know why, then adding more space would help.
Claustrophobia is the fear of having no escape and being in closed or small spaces or rooms. See Claustrophobia on Wikipedia.