When do people become ungrateful and boastful? Who are free from this?

Verses 9-11 of Chapter 11: 
And if We bestow man the enjoyment of some mercy from Us and later withdraw it from him; surely he is most despairing, ungrateful. And if We bestow upon him the enjoyment of a favour after a misfortune that had befallen him, he will surely say, "The evils have gone away from me"; indeed he is jubilant, boastful. Except those who patiently endured and did good deeds; for them is forgiveness, and a great reward.