1.Start with that it's the color of the Sun, proceed to write how good the sun is for people. Praise the Sun.
2.Proceed to write something about Dark Souls. Mention how difficult that game is.
3.Link it to various difficulties that humanity suffered and suffers throughout ages.
4.Proceed to write about how meaningless humanity's difficulties and problems are for the Universe.
5.Proceed to write about space, universe, and other possible dimentions and universes.
6.Proceed to write about all the creation. Can add some religion to it if you want to.
7.Conclude that you like yellow because it reminds you of life and happiness (and other stuff, if you want).