I was looking at some scans from this Wolverines weekly series, and Mystique is doing her thing, jerking people around for her own benefit, which brought a familiar question to my mind: Why don't people just shoot Mystique in the face the second they see her?
Every time Mystique shows up asking to join the X-Men or assist them, it's part of some long con to get her something she wants. Usually this involves endangering the lives of the X-Men, if not outright killing them, and she's OK with that. She talks a big game about loving Destiny and Rogue, but her past history is littered with examples of her ignoring Destiny's sensible (if vague) warnings to not do something. And the thing Mystique usually wants to do is not in the best interests of their happy little family unit. She sent Rogue in after Carol Danvers, which worked out fabulously for everyone *sarcasm*. She threw Baby Kurt Wagner off a cliff to save her own neck.
On the one hand, it's impressive how utterly focused she is on what she wants, to the point she frequently demonstrates a complete lack of concern for anyone else. She's smart enough to make it work, because a lot of the time she waits until she has them over a barrel to reveal herself. By the time they know it's her, she has something they need/want/care about that she figures they can't do without. And her self-interested attitude doesn't stop her from doing good on occasion. In her own series, she saved more than a few people, although it was usually because she had a personal stake in things. That's fine, it doesn't change the fact she saved those people, but it also doesn't mean you can trust her.
I understand why the X-Men aren't going to kill her on sight (though it's always irritated me how much more readily the X-Men accept her presence than Deadpool's. At least Wade has the excuse he has actual mental problems, rather than a total lack of empathy), they're the good guys. Also, she's sort of related to two of them (not to mention that off-and-on thing she had with Logan). Probably poor form to kill your friends' mom/foster mom, even if she is a terrible mom. But given her track record, that whenever she appears, it means she's planning to use whoever she's approaching for something, and if they're lucky, she won't stick a knife in her back when she's done. The only sensible response to seeing Mystique seems like it should be, "Kill her! Kill her with fire!" And she interacts with plenty of people who don't hold to any prohibition on killing, and should logically be even less forgiving of getting double-crossed.
I'm just at the point where anytime I see someone giving her benefit of the doubt, I want to slap my forehead. And I'm waiting for the time where she tries one of her "Here's why you have to help me," and the character in question calls her bluff.