This is STRICTLY the OPINION of someone who's never worn the uniform...
Being asked "Do you know why I pulled you over?" immediately brings to mind my parents asking "Do you know what you did wrong/Do you know why I'm punishing you?"
You (universal LEO you) aren't my mom...stop scolding me.
I've been stopped three times, thinking back on it, all three of them have used the "I am/from here/you did" formula. While I wasn't jumping for joy at the end of the stops, none of the three were negative experiences, even the one where I actually got a ticket.