Yes, I have met people like that, some of them being mildly manipulative and some others, just too much. I'll cite two examples:
There was this person, whose mom was friends with my mom, who I knew back at primary school who would yell at me (I covered my ears all the time lol) if I tried to talk to her in school and sometimes even insulted me and called me names. But when we were in eachothers' house or our moms were around, she was VERY nice with me and even sometimes hugged me I guess she just did it because she wanted our parents to think we're friends. I told this to my mom and she said I should ignore her when her mom's around... a few days later, she was just as nice with me at school as when we were alone, so that one worked out okay.
There was this other person, who I thought was my best friend; who lied to me, who used what I had said at times to use me to do her work for her, who stole my money and my stuff, who liked to talk and laugh behind my back with others, who teamed up with other people against me and then just said "sorry, it was wrong of me to do that...", who insulted me worse than the aforementioned person, and who liked to write all her homework and exam answers off my paper and then gloat about how she's a genius and smarter than me, and a lot of other stuff... and I wasn't even AWARE of that until a NICE friend of mine told it to me. I just lessened our relationship to acquaintanceship... and when we were beginning to get close again, she started to do everything she used to AGAIN. So I just let her go, and I'm glad I did.