What is the main character flaw of Lopakhin from The Cherry Orchard?

Lopakhin is a character who represents rising social
mobility and also comments on the way that the Ranevskys are going down socially. His
grandather was once a serf who worked on the Ranevsky estate, however, now Lopakhin is a
wealthy businessman. Being a friend of the family, he spends a lot of time trying to
help Madame Ranevsky save the orchard, but is only frustrated when Madame Ranevsky
refuses to see the necessity of action and remains focussed on her memories of what the
cherry orchard was like when she was a child. Eventually he buys the estate and he makes
a rather shocking public display where he expresses his delight in owning the land where
his ancestors once worked. His biggest failing is his vulgarity and greed. He is clearly
shown to be a symbol of the rising middle class, compared starkly to the sophistication
and elegance of the ruling class in Russia.