Like the majority of teenagers, Jack Draper could sometimes sulk on the tennis court.
There would be the obliteration of racquets. There would be furious self-castigations. There were occasions where an apology to the umpire might be needed.
All that was part of the growing up process. And it has been a key part of the 22-year-old Briton's journey to becoming a US Open semi-finalist.
"His temper boiled over at times," remembered Justin Sherring, the coach who developed Draper between the ages of five and 15.
"Did I have to call his racquet manufacturer a few times and say 'oops, I think Jack's racquets have snapped on the stringing machines that we've got here in India'?