The best summary of this passage is "Brutus, lately you have not been as kind to me as usual" (A).
In this scene from Act I, Caius Cassius is expressing what he perceives a a loss of affection from Brutus:
- he does not see "gentleness" and "love" in Brutus' eyes as he used to;
- he thinks that Brutus has become different and less pleasant to be around: "too stubborn and too strange."
The relationship between these two characters is essential to the plot, as they are the main conspirators behind Caesar's assassination.