Quote 10
"I beg your pardon, Dr. Lanyon," he replied civilly enough. "What you say is very well founded; and my impatience has shown its heels to my politeness. I come here at the instance of your colleague, Dr. Henry Jekyll, on a piece of business of some moment; and I understood ..." He paused and put his hand to his throat, and I could see, in spite of his collected manner, that he was wrestling against the approaches of the hysteria—"I understood, a drawer ..." (9.20)
Mr. Hyde is capable of repressing his emotions and impatience in order to achieve his objectives.
Quote 11
And indeed the worst of my faults was a certain impatient gaiety of disposition, such as has made the happiness of many, but such as I found it hard to reconcile with my imperious desire to carry my head high, and wear a more than commonly grave countenance before the public. Hence it came about that I concealed my pleasures; and that when I reached years of reflection, and began to look round me and take stock of my progress and position in the world, I stood already committed to a profound duplicity of me. Many a man would have even blazoned such irregularities as I was guilty of; but from the high views that I had set before me, I regarded and hid them with an almost morbid sense of shame. (10.1)
Dr. Jekyll kept the pleasurable, sinful side of his personality well hidden—i.e., repressed—in favor of appearing to be a somber man who frowns on exuberant behavior.
Quote 12
For two good reasons, I will not enter deeply into this scientific branch of my confession. First, because I have been made to learn that the doom and burthen of our life is bound for ever on man's shoulders, and when the attempt is made to cast it off, it but returns upon us with more unfamiliar and more awful pressure. (10.2)
Dr. Jekyll believes that repression yields consequences worse than Hyde’s actions.