system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is milk so much better than water after having eaten something chocolaty?

Title pretty much explains it all. My wife asked me this the other night and I couldn't think of something reasonably logical as to why this is true.
gpt
Chocolate is mostly Cocoa Butter, which is the vegetable fat from Cocoa Beans. Fats are usually very hydrophobic, which means they don't mix well with water.  After you eat chocolate, the inside of your mouth will be coated with these fats. 

When you drink water, it just flows over the fats, and you'll still have that "dirty" feeling in your mouth.  But milk, while being mostly water, contains butter fat, which makes it creamy. The butter fats act as an emulsifier, and allows the milk to better "pick up" the cocoa butter in your mouth, giving you a "clean" feeling in your mouth. 

It's the same reason drinking a glass of milk works much better that water to clear your mouth after eating peanut butter.