Monica: Hi all
Monica: I'm finally free this weekend
Monica: And I feel like meeting you guys
Mike: I felt like meeting you a week ago, and a week before that, and 3 weeks ago...
Monica: I'm sorry I was so busy
Mike: Now I'm busy, sorry
Freddie: It was Mike's birthday last weekend
Freddie: It was really important for him
Monica: I'm sorry, I didn't know 
Mike: I know when your birthday is...
Monica: I mean
Monica: I knew when your birthdays was, I just didn't know how important it was for you
Mike: You knew when it was and I didn't even get a "happy birthday" from you
Monica is free this weekend. Mike is busy. Mike's birthday was last weekend. Monica didn't send him greetings on that day.