The moment where random people (in front of you) decide to hug like they'll never see each other again.
This results in them getting in your way and you possibly tripping over them.
Erick: Aww! Sarah!!
Sarah: Erick!
*Long embrace*
You: WTF *trip* AAAH!!
Sarah: See you next period!!!
You: What is with this Hallway Hug!!!