Is Gratuity Always the Way to Go?

There’s been many cases where I’ve served large parties and have had the chance to auto gratuity them 18-20% when they have a large check. However, I feel that when you autograt customers, they are less likely to add additional tip, and I question if i shouldn’t have added the gratuity when I feel like they really enjoyed my service and were very appreciative.

Servers with more experience on this matter, what have you found to be the right way to go about this dilemma?