Talking to new sexual interests often diminishes the fantasy/lust

When talking to a person, you witness their context and their activity within it.
When only seeing a person, you only witness their body.
It leaves a hole of context, because you do not know anything else about them.
Therefore you can substitute this hole in context with your fantasy (fantasy is a context and the object is only the prop in it).
That is why often sexual desire can dissipate after talking to someone.
Because earlier, you would sharply objectify them and tie them to your fantasy context.
Now after talking to them, you witness their real context which displaces the fantasy context and ends the lust a lot of times.