Rahu was a Asur(demon) named Svarbhanu. Svarbhanu had done the
worship of the Lord Brahma and He had promised him to give him a
status of planet. In very popular incident of Samudra Manthan ,
Nectar came out and Lord Vishnu took avtaar of Mohini. Mohini gave
nectar to devas and liquor to Asuras. Svarbhanu, somehow knew
something was wrong and he changed his place to Deva's. He was offerd
nectar and when he had just drank it , Sun and Moon yelled that He
was Asura , and he is sitting here. Lord Vishnu immediately cut his
head off. Svarbhanu had already drank the Amrit and now he was
immortal.
Let's see this neutrally.
Among all the Asuras, Svarbhanu was intelligent enough to know that
something was fishy about the distribition of nector. He tricked all
the Devas and also the Lord Vishnu and became immortal.
The head part of Svarbhanu became Rahu and the body part became Ketu.
Later Brahma gave the Snake body to Rahu and Snake head to Ketu.
Image Courtsey : Google
So if we just take this incident neutrally without any bias.
Rahu has this virtues -
1. Intelligent - He knew that Asuras were being given the Liquor
2. Selfish - He didn't inform other Asuras but he, himself sat in the
line of Devas
3. Can take risk to any extent to achieve something
4. to some extent , controlled - He didnot get lured just by Mohini's
beauty