SighCraft
This mod adds an in-game block that helps express your feelings about missing modifications.
What does this block do? When you right-click on it, a message appears in chat expressing how much you miss a particular mod. The specific mod mentioned in the message can be configured through settings.
It's important to note that this image was taken during development. In the actual game, the block has a proper texture.
For using the mod in Minecraft versions 1.8/1.9, RebornCore installation is required.