It's frustrating how often he calls me about matters that are easily solved with some thinking.
I mean problems like "I added a filter to check if a value exists, but it doesn't work", but instead of choosing the "Value exists" filter he used the "Value equals (something)" filter with an empty string for (something). It never crossed his mind to try the other one, even though they're right next to each other in the menu.
(edited to be less mean)