Fortunato is quite prideful and dislikes the idea that Montressor would go to someone else for expertise on wine, which he is knowledgeable in. The narrator directly tells us this, as shown by the quote: " He prided himself on his connoisseur-ship of wine" And then proceeded to insist that he help Montressor instead of him going to someone else.
The Servants don't seem to play a particularly important role in the story, but we can infer something about them based on this quote: " given them explicit orders not to stir from the house. These orders were sufficient to insure their immediate disappearance."You can infer the servants didn't like their jobs, or you could also infer that they didn't like Montressor, because they didn't listen to him.
By the whole premise/plot of this story, one should be able to conclude that Montressor is not mentally stable, but these two quotes showcase that: " but when he ventured upon insult, I vowed revenge...." and then"but the thought of an instant reassured me. I placed my hand upon the solid fabric of the catacombs, and felt satisfied"