Why is the Marquis disappointed by the Monsigneur's grand reception?
In Book the Second, Chapter 7 of A Tale of Two Cities, the Marquis has evidently fallen from favor in the French court. For, at the reception of the Monseigneur, one of the "great lords" in power, who holds a reception twice a month in his "grand hotel" in Paris, the Marquis has stood apart from others of the Parisian Court. Not many have talked with him and the Monseigneur himself has not greeted him with warmness:"Monseigneur might have been warmer in his manner."
Angry at the coolness of the other aristocrats' treatment of him, the Marquis finds it
rather agreeable...to see the common people dispersed before his horses, and often barely escaping from being run down.
In his cruelty, the Marquis has his carriage driven with "an inhuman abandonment of consideration"; consequently, the tragic incident of the child being run over occurs that is later to be the cause of the demise of the Marquis himself.
The Marquis St. Evremonde has an over-inflated view of his powerand position in the hierarchy of the French aristocracy. He is at this sumptuous gathering, but he is not welcomed with any warmth or enthusiam bythe Monseigneur; in fact, he has been virtually snubbed. He's angry at this treatment, of course, and that anger causes his eventual demise, as noted by the previous poster.
He refers to this same shunning later when talking to his nephew Charles, who hints that his uncle may have been to blame for his arrest for treason. Evremonde remarks that it used to be much easier to get a letter of condemnation from the aristocratic hierarchy--such as he and his brother employed when having Dr. Manette arrested so many years ago. (His rufeul tone suggests he would have "taken care of" his nephew if he could have, though.)
The Marquis creates his own problems and eventually causes his own death.