I think a good example is that average normal body temperature is 98.6 F (37 C) degrees, but if you have a high-grade fever which is around 103 F (39 C) degrees

I think a good example is that average normal body temperature is 98.6 F (37 C) degrees, but if you have a high-grade fever which is around 103 F (39 C) degrees, you're feeling very ill, even though it's just a small raise in temperature.