Just like Ayselipera, I was a little naive and too gullible and trusting as well when I was 'younger' (I'm still a little young, but hey), and it really teaches you that not everyone has right intentions, even if you know them well. I was bullied very bad when I was younger (emotionally, not physically), and that also contributed. Not so much with just random people - also a little -, but more with people in school, that are being nice to you for no reason. If I can't find a reason for why someone in school is being nice to me, or is doing something to me, I get the feeling they are setting me up or trying to play a joke on me, or mocking me, because that always happened when I was younger. Also, I get the feeling that people are lying to me, when for example they tell me that I look nice. I ignore that feeling because I know it probably isn't true, but it's still there and I do notice it.