Poor grounding is a mistake that comes up a lot when people are learning electronics. This article has an excellent discussion about the various types of 'ground' references and how they interact.
Here is a thorough reference on the subject from Artech: https://www.amazon.com/Essentials-Microwave-Grounding-Artech...
A related classic is: High Speed Digital Design: A Handbook of Black Magic, https://www.amazon.com/gp/product/0133957241