You can configure a custom bot or a feedback bot that prompts your end-users to rate your customer service on a scale of 1-5 stars, where 5 is the most favorable and 1 is the least favorable.   

★★★★★ — Loved it  
★★★★☆ — Liked it  
★★★☆☆ — It was okay  
★★☆☆☆ — Disliked it  
★☆☆☆☆ — Hated it  

The system-default rating labels are as cited above. However, you can set different rating labels by clicking Custom, deleting the default labels, and entering the rating labels that you prefer.