Why would anyone want to date someone who treats their best friend like a backup plan?

If I found out that my concert ticket originally belonged to someone else, I would feel uncomfortable from the start. Imagine if that someone else was the best friend of the person inviting me, someone I have only dated for three weeks. Now that's a really big red flag. How can you ditch your friend for a girl you just met? How can you not consider your best friend before a new crush?

Some people get carried away when they like someone. Who hasn't had that friend who starts dating someone and disappears off the face of the earth? I understand the falling-in-love stage. We always find excuses to see our special someone and every shared interest feels like an opportunity. But dating and meeting new people don't require somebody else to lose their Friday plans. And above all, it absolutely does not require leaving your best friend behind.