If you like a guy, he's always on your mind--you're constantly gazing at his Facebook, you're doodling his name on your homework, you might even be dreaming about him. When you're attracted to someone, your brain has lower levels of a hormone called serotonin, which is common in people with obsessive compulsive disorder. So it's no surprise that if you like a guy, you have trouble concentrating on anything else.When you've got a crush, your brain will also release oxytocin, which can make you extra forgetful. This makes it even harder to focus on homework, sports, friends--anything other than your crush!If you can't stop thinking about him, you may also find you can't stop talking about him. If your friends call you out on always finding a way to work his name into a conversation, it may be a sign you've got a crush.
 After spending time with a guy you like, you'll just want more--you suddenly can't wait to get to school every day, you change your path through the halls to pass his locker--anything just to get a little more time together. Being around him activates the reward center of your brain, and you may begin craving that experience over and over again.Though you might be craving time with him, don't let this feeling lead you to do things that might cross the line from cute to scary. Don't show up at his house uninvited or start playing hockey just because he's the goalie. Just know that if you are always excited to see him, it means you really like him.
 If you notice another girl flirting with him and your blood starts to boil--why is he talking to her? does he like her? did she just touch his arm?!--your feelings of jealousy may mean you like him. But if you only notice him when he's with someone else, then you may just be feeling competitive, and be more interested in winning than actually dating him.Take your jealousy as a sign that you like this guy and don't let it go any further. If you get in another girl's face for talking to him, it makes you seem possessive and insecure.
 When you're into a guy, everything he does starts to seem amazing. He's nice, funny, smart, handsome--there's nothing wrong with this guy! Experts call this the "halo effect"--because to you, he's pretty much an angel. If you think he's cute, you're probably going to think everything else about him is great, too.If you laugh at all his jokes or think everything he says is genius, or you think he's an amazing guitar player (even though he only started playing last week), it's a sign you really like him.
Consider how much time you spend thinking about him.
Spend some time apart and notice if you're counting the minutes to when you'll see him again.
See how you react when he spends time with another girl.
Notice if you idealize him as the perfect person.
{"src": "wikihow-all_test", "title": "How to Tell if You Like a Guy2"}