Dear friend, I really sorry that I did not come to you. Sorry, that I left you alone in the cafe. Next time you can do the same thing with me or you can hit me or tickle me, haha. But now, I can explain why I did not came. In the morning, when I was ready to leave home I was kinda sleepy and I took with me my mothers keys. And we haven't got 'emergency' keys. So my mom called me and after school I run home. So I really sorry. Please, can you accept my apology?
Hope to see you soon,
Your friend Sergei...(или твое имя).