making a mountain out of a molehill

Making a mountain out of a molehill is a common saying which is used when you make a major issue out of a minor one and exaggerate the importance of something. This is usually spoken in the negative as you ask someone not to make a mountain out of a molehill that seems to be turning a very small issue into a big problem. They tend to exaggerate details of something and make it more important than it is.