If your jealousy drives you to work hard to follow the example of someone you're jealous of, it's healthy and positive. If you are feel jealous without work, this is a moral disease, you have to fight it and overcome it, or it will destroy you, and turn your life into hell.
On the other hand, people differ in their abilities to worship, and the important thing here is for the person to notice how much he obeys Allah. How far he obeys his commands, refrains forbiddens (haram acts), and how he deals with people. This is more important than desirable worship. Person may be very praying and fasting, but he does not refrain from falling into haraam things. This is of no value to his prayers and fasting.