I dare not even think about any oil with my superfine hair! I know argan oil is in, but there is no way I am letting it near my hair. I did use a coconut oil shampoo from India in my teens though. It made my wavy hair really glossy and beautiful. I guess you ladies who use coconut oil have thick, coarse hair, right?
Oh and I did sometimes mash a very ripe avocado and use it as a pre-shampoo hair mask in my teens. I kept my hair longer then.
Nowadays I wear a layered bob and try not to weigh it down.