Yeah, the two pennies are basically saying bad service because it's more intentional than not leaving any tip. FTR I've done this when the service was really bad. I was going to say something to my server but they disappeared. I left my two cents but most likely the point would be lost.

In the culture of the United States service industry, leaving a 2 cent tip (specifically two pennies) is a deliberate and highly insulting "coded" message. While leaving no tip might be interpreted as a simple mistake or forgetfulness, leaving exactly two cents tells the server: "I did not forget to tip; I am intentionally giving you the smallest possible amount to show you that your service was abysmal." It is considered the ultimate "slap in the face" in the hospitality world. The phrase "my two cents" usually refers to sharing an opinion, and in this context, the "opinion" is that the server failed completely. It is a very rare and aggressive gesture, and most etiquette experts suggest that if service is truly that bad, it is much more effective and professional to speak with a manager rather than leaving a passive-aggressive "insult tip." In the modern era of digital payments, this gesture has largely faded, but the "two-cent" symbol remains a powerful emblem of deep dissatisfaction in traditional dining.