I would say that it certainly does frustrate your teacher to have to lose 10 valuable minutes whilst the pupil consents to start!!
But seriously though, now you've identified how you're thinking and feeling, you can sit down and work yourself through why it's bad for you and, perhaps, you might want to do what I would do under the same circs and give myself a good talking to?? For instance, if it were me, (and note that I said '
if it were me' here and am
not bagging you - you must work out your own lecture!!!

) I'd be reminding myself (in advance, one doesn't have time for this at the lesson) how I was wasting my time, my teacher's time and my own money etc., how I was actually preventing myself from making better progress, how not even the best player that ever was got it perfect 100% of the time and how even pros have off days, how many people my teacher would have heard that were far worse than me and also, heck, I was doing this for fun, so why give myself such a hard time about it and making myself look such a numpty into the bargain!!??

Also, I would make up my mind to just do as I was told at once at my lesson and then, take a deep breath when asked to play and just get on with it. My teacher is there to help me, so my co-operating fully with him/her is in my own best interests.
Something that may be worth your considering honestly is, are the pieces you're doing etc actually too hard for you, (which looks possible as you cite Grade 1 scales and Grade 2 pieces)? When I felt that I was being given stuff that was beyond my level at the time, I hated prac and my lesson and felt very unwilling. Once I'd carried my point that I felt it was too much with my old teacher, (not my present one, she's
much better), we dropped back to where the course actually was taking me instead of racing on to something that wasn't specified at that point and I started to enjoy it once more. We all want to be virtuosos somewhere inside, but we all have to take the needed time about it so, if you're trying to race ahead too fast, (or are being pushed ahead too hard), then say so and drop back to what you feel is right for you and see if that helps. There'll be less fear of gaffing up if it's not too challenging. It should challenge us a bit, but not too much.
Good hunting!