First, Pip is surprised that there is anyone in the garden. He is not used to seeing so many people around Miss Havisham’s house. She is a recluse and does not get many visitors.
Never questioning for a moment that the house was now empty, I looked in at another window, and found myself, to my great surprise, exchanging a broad stare with a pale young gentleman with red eyelids and light hair. (enotes etext p. 63)
Of course, the pale young gentleman is also surprising because of his peculiar behavior. He immediately asks Pip to fight, but is completely friendly and shows no hint to anger.
“Stop a minute, though,” he said, wheeling round before we had gone many paces. “I ought to give you a reason for fighting, too. There it is!” In a most irritating manner he instantly slapped his hands against one another, daintily flung one of his legs up behind him, pulled my hair, slapped his hands again, dipped his head, and butted it into my stomach. (p. 63)
Pip feels very guilty about fighting with the pale young gentleman. Later, he learns that Herbert Pocket is actually a very nice young man, and the two become fast friends when they live together in London.