I-

Used by people who are "speechless" which could be just an excuse to end a conversation, as it's a short response that's hard to respond to

Person 1: Hey, want to wrestle with me at school?

Person 2: I-

Person 1: You gonna answer or are you gonna just sit there and act stupid?

Person 2: Fuck you bitch *slaps*

Person 1: *beats up*

Person 3: *breaks up the fight