Hmm, I'd say I'm actually neither that jealous nor competitive. The SLI I know can be competitive, similar to what LV said. My IEE friend is pretty easy-going. He can be competitive, but it's in a very playful way. The LSEs I know are very competitive on the job and one of them has a history of jealous behavior (in a party setting with lots of unknown people, alcohol, and the outgoing other half in their relationship [which has since ended]).