Somewhere in the city, you caught your eyes on a member of the opposite sex. He could be having lunch, breakfast, or having coffee, and you noticed he's alone.

As you focus on what he's doing, you lose awareness of the surroundings.

He seems slightly preoccupied though, while having his lunch/breakfast/coffee. He is looking at his mobile phone, wearing a slight smile and pushing keys on the mobile phone's keyboard. Occasionally, he looks up from his mobile phone to look at his environment and look around the sea of people surrounding him.

You looked around for a seat, and the only seat available is the one near him, and so you approached him, and asked "Is this seat taken?" He replies with a "No, it's not. You're welcome to have it". You replied "Thank you" and sat down beside him.

Casually, a conversation begins. Even though you remembered feelings surrounding the conversation, you no longer remembered who started the conversation, as it doesn't seem important. What's important was that the conversation was fantastic, funny and enjoying , even though it's nearly the same kind of conversation you have had with many others before.

And so, though you wished that it continued on forever, each of you have different things to do for the rest of the day, and you parted company. At the end of the day, as you thought back and reflected upon the event, you realized that neither of you asked for a way to keep in contact with each other.

What do you do?