Scott:
when you finally realized his laugh was the only thing that made your heart race. You were his best friend at the time and when he laughed, you realized you loved him. Much more than friends.
Stiles:
the first time you looked into his eyes. They were the perfect shade of light brown and that made all your insides melt. It was just how his eyes stayed connected to yours.
Derek:
after he saved you from Kate's rathe. You never saw Derek in a loving way until that one night that he literally swept you off your feet and away from death. That's when you realized he was the special one.
Isaac:
when you started noticing how he played lacrosse. He played it with such passion and would always mention he played hard for you. It made you nonstop smile. You knew from the point on he was amazing.