It's one thing that you feel that you are so awesome that you think that you are the savior of your people and that they should follow you. That's a bit grandiose.
He was a good moal standard for his time and he recognised this. At least, let´s say he thinks he was a very good one.
Don´t see much of a big deal in that one. I always thought it was very silly of a lot of saints to be "humble" to what really turned out to pretend they were horrible monsters while everyone knew they mostly were really good people.
It gets pathetic and useless. If he has high image of himself, well, he oughta. I mean, the guy could walk on water, and the power supposedly came from God. If you are not very very awesome then, then I don´t know when.
But when you feel that you are so awesome that not only the messiah but the now you view yourself as the Son of God, the inheritor of the universe and then it doesn't stop and now you now think you, yourself as God.
The problem is that the character of the bible (I talk in this terms for commong ground, after all we are talking about the char from the gospels. Wheter everything written there was accurate or not is besides the question, but we´ll treat the "character" in the way the gospels portray it because that is the source you are using when he says he is "all that" ) had revelation from God that he was, in fact, that awesome.
If God tells you something and leave you a memo you can walk on water to prove that he is God and that what he is saying then must make sense, you either believe you are being "x"ed (Jamy Kenedy Experiment!) or more realistic for that time, you actually are as awesome as the voice that lets you walk on water say you are.
In other comments he said contrary things, mind you. In some he is the incrediblesness incarnated, in others he says "Why do you call me good? Only God is good" in other he says "I only act in behalf of my Father"
And so on.
If you are gonna judge the man by what he says on the bible, then the miracles are part of the context. So... well, not so much narcisism, but "realism (again, talking about the reality of the character of the book, not actual reality necesarily)