I think this could be answered a lot of different ways, but here is at least something to get you (hopefully) started:
Some issues are more important to us than others because they may affect us more. If you are a person of color then issues surrounding racism may affect you more than someone else, so the problem may be more important to you than to someone else who "doesn't care." If you are hungry getting food might be a more important problem to you than homework, but the homework may be a bigger problem to the teacher, etc.