I'm 26 at the time of writing and have gotten my brows done since I've been 12. I have NEVER had someone spend as little time on my brows as they did here. I can understand some practitioners being faster at threading than others. But the girl assigned to me just whizzed through the brows, curving them instead of creating more of an arch, and took less than 5 minutes total time.
When she finished the brows, there were plenty of stray hairs left around my brows and I had to ask her to go back and clean up, as well as adjust the shape a bit. She didn't say anything, and kept a tight smile on her face, but I got the feeling she was annoyed. For $10 you (the salon) can absolutely do better, and you (the customer) should go elsewhere until they do.