Leading lines are a wonderful compositional tool, but sometimes it pays to cut them free
Leading lines are one of the first compositional rules that you're taught in photography, and with good reason. They're highly effective when it comes to directing your viewers' eyes to your focal point and maintaining their interest in the photo. Leading lines don't have to be 'real', either; implied lines, for example eye-lines, are just as effective at guiding someone across an image as a row of rooftops or a railway track.
Sometimes, however, the absence of lines from your photo can produce more powerful, more compelling photo. If you set your focal point against a consistent background, for example a perfect blue sky or a lush expanse of grass, the elimination of distracting elements can ensure that the focal point becomes even more prominent.
The same goes for already-strong compositions, for example those where there's a strong contrast between the focal point and the background. If a leading line isn't contributing to the composition positively, then you're better off omitting it.
If you've the option to include or exclude leading lines from your photo, ask yourself: 'Do they improve the photo as a whole?' If yes: include them. If no: exclude them.
You'll often find that the more elements there are in your photo, the stronger the need for a leading line or two to ensure that people know where to look. Simple shots, where the focal point is much more evident, are less likely to need help.
Don't forget, it's almost impossible to exclude leading lines entirely from your photos, whether it's a blade of grass bending in the wind or a bird's curved bill. What you need to decide is if a leading line will add to, or detract from, your final photo.