There's an assumption that good photos are high-contrast photos. This isn't always the case.
Before we leap into a discussion about the merits of high- and low-contrast photography, it's probably sensible to have a quick refresher as to what contrast is. Most simply, it's the degree of difference between the lightest and darkest parts of your photo. More difference means more contrast and, usually, more contrast means a more dynamic photo.
Think of it this way: to which is the eye more likely to be drawn: a grey kitten photographed on a grey background, or a white kitten photographed on a black background?
When we're talking about colour contrasts, red decorations on green Christmas trees look so appealing because red and green are contrasting colours; they sit opposite each other on the colour wheel. The same goes for golden sands and blue seas and skies, and yellow-striped bumble bees on purple flowers.
We use these differences in black and white and opposing colour combinations because they work, but contrast is something on which photographers can become over-reliant when it comes to producing compelling images. It doesn't always have to bowl you over.
In particular, foggy scenes tend to be very low on contrast and there's nothing about a well-composed, well-exposed fog photo that couldn't be appealing. Scenes where there's very little difference in colour and tone are often very evocative, and sometimes even peaceful.
In particular, low-contrast photos are often about subtlety and can convey a sense of innocence. While high-key photography is often bright and bouncy in its mood, it usually comes with a good dose of innocence about it, too.
By thinking more low-contrast, you can open yourself up to much more dreamy, romantic photography that's a little more subtle and a bit more ethereal. There's a delicacy, and fragility to low-contrast photography that shouldn't be dismissed. Instead, embrace it.