Dorfromantik

Dorfromantik is a great example of a well defined, highly polished, relaxing game. It reminds me very strongly of the Carcassonne board game where you have to place tiles on a board, and the edges have to match the others around them. Here you're allowed to place them wherever you like, but you score more points (and extra tiles) by placing them correctly. As you place tiles, some of them contain "quests" where you have to build fields of a certain size, rivers of a certain length etc. There are also new tile types that unlock once you reach certain score milestones. It has a lovely relaxing soundtrack, and is really pretty to look at.

Pros

Really relaxing gameplay
There are beautiful little details on the tiles. Some water tiles have swans on them, sometimes if you build houses next to a river one of them turns into a water mill, for example
Clever scoring mechanics for tile placement
Quests appear for placing certain configurations of tiles
Beautiful background music
After a while you unlock more colour schemes for tiles (where corn fields might turn purple for lavender fields)
As you hit certain score milestones, you unlock new buildings. One of these is the water railway which lets you combine rails with water tiles
There are a bunch of different ways to play the game. Classic mode with scoring, creative mode where you can just build pretty landscapes, quick mode, hard mode etc