Natural instinct propels you to fight or flight, to keep your neck above all else.
This is what Esther did. Her uncle was asking her to risk everything to save her people, the Jews, who were decreed death in a rash issue of legislation from a despot. Her knee-jerk reaction: But I could die if I dare to approach the emperor unbeckoned.
Unlike animals, humans can sacrifice themselves for others. A soldier throws himself on a hand grenade to save his buddies. Jesus throws himself onto the cross to save all humanity. The missionary throws himself into the mission field risking Ebola infection.
At some point, looking out for #1 becomes sin.
For some, thrills-seeking is an adrenaline rush, to have brushed with death and escaped unscathed.
A Christian is not called to dare-devil. But he IS called to sacrifice up to his finances, time and even life in order to reach others with the Gospel. To renege is sin.