Without tribulations, there would scarcely be any progress in this regard. Why would their be, as in times of comfort and plenty, when there is essentially no stress or competition, it is not difficult to get along. One can see this every day. Children at play, who all have the same toy, engage themselves in playing with the toy and ignoring the others. But give only one or a few the toy, and place the others in want, and a drama ensues.
Some entities decide to enjoy the toy vicariously, reveling in the enjoyment the other is having.
Some entities, consumed with envy, plot how to secure the toy for themselves. Some entities, having learned how to manipulate social situations, may wail and cry, seeking what they term justice. Where this is a simple example, one every adult can relate to and sees everyday, most tribulations are born in silence and are hidden from view. This does not change the nature of the action, however. Serious tribulations, such as a debilitating disease, also have an effect on the entities spiritual growth, and not altogether a negative effect, either.