I usually tell my students something like this: that the test is to help them (and their teachers) understand them better--how they learn, how their minds work, other factors that affect how they learn. To do that, I will ask them to do a variety of activities, including items that are easier for them, and ones that are harder for them, because we want to get as good a picture as possible of their whole range. I say that I will probably find strengths and weaknesses, because everyone has strengths and weaknesses, and there's nothing wrong with that. All I ask is that they do their best, so that our testing reflects them accurately.