Some good advice my mom mentioned
I think this is a good way to approach life. You should feel like you're able to trust people, yet you should know when to cut them out of your life.
I especially believe in this quote because it applies to me a lot personally. I remember being very judgmental of people, more specifically girls my age that I thought were pretty, back in high school. I was a total bully back then because I seriously needed a big heaping bowl of self-esteem to coax me into letting down those walls I put up. I still have that same insecurity, but I can control it when I'm in a good mood.
It's also good to cut people out of your life when you feel like they're not being too good to you anymore. This has happened to me a lot. The first incident was when my childhood friend since kindergarten abandoned me. I never got a reason from her, but I assume it's because of my anxiety, as I was no doubt too much for her to handle back then. The same thing happened with a lot of my classmates in high school. I've cut them out of my life entirely now because I don't expect them to want to be friends with me again after the way I treated them.
Then there are people who are just plain not worth it. I had this classmate during my first year of college who seemed perfectly normal and nice at first but then turned out to be a total dick as I got to know him. He was absolutely disrespectful! He was always in a negative state of mind and had a nasty habit of taking his anger out on others, especially me. I'll admit that he was nice to me sometimes, but only when I was actually being useful to him like when I pointed out where he left his Dungeons and Dragons book when he was getting pissed off looking for it. Even though he thanked me for being "helpful", albeit in his good ol' sarcastic, condescending way, I was still scared he would lash out. He has done that a plentiful amount of times, and it's always been scary. When it's not scary, it's just downright hurtful and aggravating. When I lost my patience with this man, I gave him a piece of my mind, being the overly assertive individual I am. When a staff member wasn't there to reprimand me for my aggression, he would step in and hurl a shit-ton of insults and other degrading statements. He even made me cry a couple of times, which I'm surprised my peers gave me sympathy for because I was so emotional back then that even someone politely declining to go out someplace with me would throw me into a sobbing fury. After months of therapy, I soon decided this bad person was one-hundred percent not deserving of my trust or need of approval from him- and that's coming from someone who had traded her dignity for beauty just to get people's respect many times!
To summarize, be willing to let your guard down, even when intimidated, but don't feel like you have to put up with people who aren't in the right mind to understand you enough to do so.