system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the appeal in carbonation in drinks? Why do uncarbonated beverages taste fine, but flat soda tastes disgusting?
gpt
Soda water by itself is quite bitter.  In a pop this bitter is contrasted by the large amount of sugar (sweetness) they have.  When a pop looses its carbonation, the CO2 has left the beverage.  This means that the sweet no longer has the bitter to balance it out, leaving a disgustingly sweet liquid behind.