As Simba walks up to the front of Pride Rock, everyone is seeing him remembering who he is. Simba's kingdom thinks of him as a leader, strong, and not full of himself now.
Before he become king of Pride Rock he thinks of himself as a chill person, and doesn't really care about what happens to Pride Rock.
Before Simba returns to Pride Rock Nala thinks of Simba like he doesn't care and I should go find someone who does. After the fact, Simba and Society see him as a leader and that he actually does care.