Eyebrows can be one of the most underrated things about the face. How often do you see someone all dressed up, wearing nice makeup yet also wearing ungroomed eyebrows? It is like having a nice coat of paint on your door and leaving the rusty old handle. There are not many of us blessed with the perfect shape, no-maintenance eyebrow. We have to trim, pluck or shape them so that they add to our appearance rather than detract.
To illustrate a point I have (in a very amateurish way, admittedly) played with the Mona Lisa and her looks. The first image is the real Mona Lisa. As we know she has no eyebrows and this makes her forehead seem very large but it also makes the 'overhang' above her eyes seem quite heavy. Her face seems unbalanced and her eyes quite small. This is the same effect that you get when your eyebrows are plucked to a fine line. Why bother? Just shave them off!
In the illustration below poor Mona has almost joined the ranks of the mono-brow. She is a member of the great unplucked, and look what it does to her face. She might as well wear a dotted line across her face saying 'divide me here'! The heavy brows chop her head into two halves, but even worse, they close in her eyes and add 10 years to her age.
In the final image we find Mona with groomed eyebrows and what a difference it makes. Somehow it opens her eyes up and they become more noticeable. The forehead is softened and the whole face more balanced. Just imagine how good she would look with a professional makeover instead of a poor image edit!
Your eyebrows are the frame for your eyes and the balance for your facial features. Remember that they should match your facial proportions too. If you are delicate with little features then keep your brows slim lined. If your features are more generous then your brows should be a little thicker to maintain the balance. No matter what you look like, your brows need to be attended to.
If you would like to know more about how to shape your own eyebrows there is a good little article at NZGirl.