City, who beat Chelsea 1-0 on Saturday, are 11 points clear of second-placed Liverpool after 12 straight league wins and closing in on a fourth English title in five years.
Guardiola cited the example of full-back Joao Cancelo, who suffered facial injuries in an attack at his home last month.
Cancelo has started all three of City’s games since, helping them come through a tough period in which they have been badly hit by a coronavirus outbreak.
“In this season there are personal problems for the players,” said Guardiola. “They are human beings, they have families, there are problems sometimes.
“For example Joao — he had an incredible episode a couple of weeks ago with the family at home. How should you react in that situation?
“The way he reacted was exceptional. He said he wanted to play against Arsenal, in the cup (against Swindon) and play Saturday.”
Guardiola said he was satisfied more by the continuing success and high standards of his side than the trophies they win.
“These guys, every single game, give everything for this club and this is so hard to find in modern football,” he said.
“We are humble enough to run without the ball and try to do our best every single game. This is my — our — biggest achievement as a club, as a team, by far.
“To win and win after four years, in this country, in this league, this is outstanding. This, for me, is the best title I have or will have when I leave Manchester City.”