Some people already know everything, and are more than happy to let you know it, even when they claim to be asking your opinion.
In the Zen Buddhist tradition, there is the parable of the tea cup that can help us from being one of those people.
A scholar from the west knocks on the door of a venerable zen master and announces, "I would like to learn from you."
The zen master invites him in and the scholar proceeds to tell the master everything he knows about zen. The master waits for his visitor to stop, but he just keeps going. In time, the master starts to prepare tea. He boils the water, puts the tea in the pot and waits for it to steep; he prepares the cups. All the while, the scholar talks.
The zen master begins to pour tea for his guest, slowly and carefully. When the tea reaches the brim, the master continues pouring and the tea runs down the side of the cup and across the table. The scholar leaps back to avoid the hot tea and says, "Stop! It's already full."
The zen master stops pouring, looks at the scholar and quietly says, "Your mind is like this cup; it is already full. You must first empty your cup if you want to taste my tea."
The lesson here is that if we want to learn we must stop talking and listen. We must understand that others have much to teach us if we allow them to do so. We need to remind ourselves that it is okay to say "I don't know."
We must do our best to not be full-cuppers.