If people look at just the sun sign cusp they are fooling themselves. If they have a chart done it will give an exact placement for the Sun sign. What is even more important and relevant and will affect the person most significantly is whether or not the ASCENDANT is on a cusp.
I just finished working on a chart for a man who was having a difficult time trying to understand himself. His sun sign wasn't on a cusp - but his
Ascendant Sign was. He had an Ascendant of 29 Gemini 30. Which translates into 29 degrees 30 minutes. He was 30 minutes away from being a Cancer Ascendant.
In real life he lives like a Cancer Ascendant, but he reacts to things as both a Cancer AND a Gemini. He was wrought with confusion and could not figure out who he was. He has a much better idea now and is much more focused. The chart helped answer many questions for him and helped him in understanding who he was and WHY he did and felt as he did.
Sun sign cusps are a rip off.