We all have that friend, the "OMG he called me pretty, he totally wants me, he's so ugly, what a creep!" And some of us are that friend. But whether you are that friend, or have one, being called pretty is not always creepy or bad.
Now in my experience girls usually only get antsy about being called pretty if the guy is unattractive. I mean if Channing Tatum cat called you from down the street, you'd probably pass out. But when the sweaty kid with the mustard stain on his shirt gives you a genuine compliment, it's suddenly creepy. But why can't all of us girls just say thank you and move on. Why do we have to rudely reject someone who gives us one compliment. If they aren't torturing you with unwanted affections, just thank them and move on.
If it's someone constantly showering you with compliments and soliloquies of their love for you, and you've told them to back off, that's when it's time to be alert. Block them on social media, or tell someone that you trust. I have had creeps at my jobs, who have showed up specifically when I was working and made inappropriate comments. I was sixteen at the time so I told my manager, and the guys harassing me had to be banned. But sometimes people don't know when to stop, so if you ever genuinely don't feel safe, please tell someone who can do something about it.
Another important thing about receiving compliments from someone is don't go overboard with the "He/she makes me feel unsafe." Because if it's a one time compliment that was not threatening, and you're lying or exaggerating to blow it out of proportion, you can really ruin somebody's life, job, or reputation. If a teacher compliments your nice hairstyle, don't run to the dean. You can cost this teacher their job, and they might not find another one in that field. If you are mellow dramatic it will really embarrass somebody who was just being nice. And how would you feel if somebody rejected you being nice then had you labeled for giving a simple compliment.
Just remember to try and be gracious to people, don't take everything so personally. And don't freak out when someone who you don't deem "attractive" or "your type" compliments you. Just try and be civil and pleasant unless it really is a scary situation.