Does people trying to help you or assume what your trying to say bother you? Or just me

Does people trying to help you or assume what your trying to say bother you? Or just me Like I’ve had a stutter pretty much my whole life. Back to my question, this morning I was getting coffee and I was trying to say “medium vanilla latte” but the cashier kept like saying things back to me trying to guess or assume what I was trying to say. This happens a lot and though a minor inconvenience it has kind of started to bother me.