I would agree that Julius Caesar had become arrogant, boastful and overly ambitious. On the morning of his murder, he had decided to stay at home. His wife Calpurnia had convinced Caesar to use her anxiety over her nightmare as an excuse for not stirring out of the house on the Ides of March:
Alas, my lord,
Your wisdom is consumed in confidence!
Don’t go out today. Call it my fear
That keeps you in the house, and not your own. We'll send Mark Antony to the Senate-house,
And he shall say you’re not well today.
Let me, on my knee, win this argument.
Finally, Caesar agrees to stay home for Calpurnia's sake:
Mark Antony shall say I’m not well,
And, to make you happy, I’ll stay home.
Then Decius Brutus comes on the scene. He uses flattery to trap Caesar. He begins to interpret Calpurnia's dream in a positive light. He begins to say things that appeal to Caesar's desire to be crowned king. In no time at all, Decius Brutus has convinced Caesar to appear at the Capitol:
This dream is interpreted all wrong.
It was a fair and fortunate vision.
Your statue spouting blood in many pipes,
In which so many smiling Romans bathed,
Signifies that, from you, great Rome shall suck
Reviving blood, and that great men shall ask
For tinctures, stains, relics, and recognition.
This is what Calpurnia’s dream means.
Then Decius Brutus adds that the Senate has planned to crown Caesar king. Caesar falls for Decius' flattery:
I have, when you’ve heard what I can say
And you know it now. The Senate has concluded
To give a crown to mighty Caesar this day.
If you send them word you’ll not come,
They may change their minds.
Obviously, Caesar is interested in receiving the crown. His response to Decius' flattery is that he will now attend the Senate meeting. This response proves that Caesar is ambitious. He desires the crown and will go to the Senate to receive his chance at the crown:
How foolish your fears seem now, Calpurnia!
I’m ashamed that I gave in to them.
Give me my robe, because I’ll go.
Caesar tells Calpurnia that her fears are foolish. He decides to go to the Senate because he wants the crown.
No doubt, Caesar had been convinced by Calpurnia to stay at home. Then he hears Decius' comment indicating that the Senate has planned to present Caesar with a crown. Caesar, in his ambition, decides he will go to the Senate and receive his crown. He desired the crown more than he desired to please his wife.