Negative experiences in your first six months as a trainer.
I think for me I worried about doing a good job with each client. Confidence came with experience. I didn’t necessarily have any negative experiences, but I do remember a rookie mistake. I had just finished a cardio fit test with one of my first clients, and I forgot to have her remove the chest strap when were done reading the results. She forgot, too, and ended up driving home with it still on her. Oops!! (She did return it). 🙂