OB/GYN question

Ok so I went yesterday to a new dr and I liked her. I felt very comfortable and the office was nice. However, after the assistant weighed me (cringe) and told me to get undressed for the exam, I told her that I had to go to the bathroom. She told me where it was and I said 'Do I need to leave a sample?' She said no. So I didnt but I felt weird bc every time I have been to the gyn they take a sample. When I saw the dr she said 'You left a sample, right?' I told her the asst told me not to She said I could wait and drink some water so they could take one but I didnt want to wait.

Now I am annoyed - should I go back next weekend to do the sample? How important is it?