Saruman

[Maédhros]

You're absolutely correct.

“Well,” thought I, “if they’re such fools, I will get ahead of them and teach them a lesson. One ill turn deserves another.” It would have been a sharper lesson, if only you had given me a little more time and more Men. Still I have already done much that you will find it hard to mend or undo in your lives. And it will be pleasant to think of that and set it against my injuries.’
‘Well, if that is what you find pleasure in,’ said Frodo, ‘I pity you. It will be a pleasure of memory only, I fear. Go at once and never return!’

I think that it was the way of JRRT to show us how low had Saruman fallen, and how much had Frodo grown in the end.

Saruman rose to his feet, and stared at Frodo. There was a strange look in his eyes of mingled wonder and respect and hatred. ‘You have grown, Halfling,’ he said. ‘Yes, you have grown very much. You are wise, and cruel. You have robbed my revenge of sweetness, and now I must go hence in bitterness, in debt to your mercy. I hate it and you! Well, I go and I will trouble you no more. But do not expect me to wish you health and long life. You will have neither. But that is not my doing. I merely foretell.’

It was more of your reason # 1 than 2 i would say.