Okay, let's go.
First thing I like about Jean, is the dichotomy. The passive nice every day girl, that with anger can switch into a person that can be really cruel. The struggle between exploring your powers and being a bright star that scares everyone, or keeping it down and staying in line like a good girl
Her compassion and empathy for people, wanting to save them, even if it means sacrificing herself.
Her stubbornness that caused her to reject a future being forced on her, and only accepting it on her own terms when she was ready (Rachel appearing to Jean and calling her mum, Scott proposing marriage when she had memories of him doing it to Madelyne and Phoenix)
Her teasing playfulness that she has with Scott, Ororo, hank, Angel and Bobby. I live that her sense of humor doesn't have to do with making quips.
I find it interesting that for a long time she held back her powers because she was scared of them, then she held herself back because her friends were friends were scared of her becoming to powerful, until she got fed up of and decided to stop, and then her friends and family kept trying to get her to power down. As apocalypse put it
Jean grey is hopeful, she is passionate, she has a lot of love to give, she wants to help everyone, she wants to be the perfect good girl, but she's also angry, and cruel, and can't help have wandering thoughts about men like thunderbird, Wolverine and Fantomex, she can keep a grudge for a long time, but they fizzle out if the person apologizes sincerely. She's the kind of person to break you apart in anger then out you back together in remorse.
She's killed billions as dark Phoenix so she tries to have a no kill policy
Let's not talk about her Jealousy lol