Final Fantasy XI, death is a fairly major penalty; in other games, such as World of Warcraft, death is not much more than a slight inconvenience.
But even if death results in nothing more than respawning a few seconds later in Star Trek Online, when the group is together, people can act differently. So what do you do? Do you try to take enemy attention so that your fellow party members can get away? Do you make a run for it, figuring that whatever's coming for you will eat someone else first? Or do you try to go down with guns blazing and make as much of a dent as you can?