Hi dcscccc -
Generally, the most similar human being to me are my 3 brothers. However, for a few traits–height, body mass, competitive approach to sports and games, disposition toward engineering instead of art–my cousin Dan is closer to me. I think Dan is more similar on about 10% of my traits; but take that with a grain of salt, because I haven’t done a rigorous analysis. My brothers are more similar on the remaining traits.
It works the same way in the primate family. Overall, chimps are closer to humans than gorillas are; but on 15% of traits, gorillas are closer to homo sapiens. Since I’m sure you are curious about how this might be, I refer you to the previously mentioned concept of incomplete lineage sorting. At first glance it seems counterintuitive, but it’s one of the more important insights of population genetics. It even applies to allele distribution among humans, It is very well established science.