Selection from – Ethics – Part III. On the Nature and Origin of the Emotions (Page 8)

Spinoza's Words: (when a hated object is destroyed pleasure results)

Proposition. XXIII. He who conceives, that an object of his hatred is painfully affected, will feel pleasure. Contrariwise, if he thinks that the said object is pleasurably affected, he will feel pain. Each of these emotions will be greater or less, according as its contrary is greater or less in the object of hatred.



Here Spinoza comments on the emotion of pleasure experienced when something we don't like is diminished. The greater the diminishment the greater is our pleasure.

Spinoza has many other similar explanations of various other emotions; connecting them all to increases or decreases in pleasure or in pain.