Like I said, think of it as service. Being honest and open about your feelings - even the negative ones - is another way of making yourself available to your Master. You wouldn't hide your body from Him: don't hide your mind either.
Look at it this way: saying "This doesn't work for me" isn't telling Him not to do it. He might even take it as an encouragement to do it more, just to be cruelThe important thing is to tell Him what's really going on.