I have had 5-6 different ones over the years and only had one who thought he was big and bad and would bite but it doesn't hurt....
No.not all leopard geckos are mean.it depend
It depends on how you treat him/her and if you bond much. I had one male and he got tame enough that I could hand feed him pinkie mice and he would crawl in my hand
I had 2 one of them were horrible (i never handled him) but the other one was a female and she was lovley! Femals geckos have the best temperment!
No, not at all. When you get a gecko, it may take a while for it to get used to you, but if you treat it right and get it from a knowledgeable breeder; the gecko won't be aggressive. Most of the time, geckos only are aggressive when taken by surprise; example, if you stick your hand in the cage and grab the gecko without it seeing you first. But all in all, the leopard gecko is actually the nicest and most tolerant of geckos.
We have 10 geckos right now. Most of them are really nice. It depends how much works you take in hand taming them.