system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does CO2 make a drink like Coke feel 'fizzy' while nitrogen gas makes a drink like beer/ale feel smother?

Is it to do with the slight difference in charge between the C and Os or something about the kinds of receptors that are stimulated?
gpt
Bubble size.  imagine bubble wrap for mailing packages - it comes in different sizes, some with lots of little bubbles and then some with fewer but bigger bubbles.  

In beer, N2 makes lots of little bubbles while CO2 makes fewer big bubbles.  And just like how fine silt feels smoother than rough sand in your fingers,  finer bubbles feel smoother in your mouth.