Depending on how you see it, the Sun sign is either the most overrated or vital placement in the chart; its how most people identify you on a surface level when it comes to Astrology—the Sun being ruled by Leo makes it more ironic that it gets the most attention.
The Sun signifies many things : the personalities and images we want to take on, our life force, our interests, what we take pride in, and the things we shine a light on—intentionally or unintentionally. It can also signify our Fathers, since Father Figures are supposed to teach us courage, pride, and healthy ego - they lead by example.
I’ll use my Sun Placement as an example :
I have my Sun in the 8th House - in the sign of Leo at 29° Degrees. The 8th House deals with personal themes and events in our lives - what and who makes us vulnerable. For this reason, we can find many Astrologers (or people who are obsessed with Astrology) who have this placement, since Astrology is a self-study. And look what I’m doing now : shining a light on Astrological topics.
Let me use a celebrity example :
Kurt Cobain had his Sun in the 6th House - in the sign of Pisces at 1° Degrees. The 6th House deals with errands, physical tasks and duties, and overall health. Cobain had a fixation with specific human body parts - he’d make collages of dolls, one of Nirvana’s albums was titled “In Utero”, and in his interviews he’d talk about his obsession with anatomy in general.