You know, when you think it's rude when someone called your name and then you answered "Who are you", what about the person who called your name while forcing you to say something back whether you remember him/her or not? It's ruder, imo.
...I knew it, it's you...You're "Tsuttsun" aren't you!!You gave me a shock there.
Haven't seen you since elementary school!Erm... where's there an empty seat...You really haven't changed at all... or rather, you haven't changed at all, have you!?
What the heck is going on!?Okay...Who are you?
An acquaintance?Over there!!Oh?What happened? Did you transfer again?Can I be your neighbour?Eeeeeh!?Reunion?