Business is a very important thing, and as a result, it becomes the object of cartoons. The theme of business covers a broad range of topics. They can be explicitly about a certain business, like Wiley's the new irs, or they can be broader like Feiffer's mr sunshine. Some specific topics which are common include discontentment with one's present job like your decision by Feiffer and trying to get ahead like in another of Feiffer's cartoons, rat race. Other topics include, but are certainly not limited to particular aspects of generic companies, such as tech support and plumbers by Wiley. Trying to make an easy buck, as in Wiley's nude and Watterson's tooth fairy and insurance is another example.
Recently, Doonesbury ran a series on how a college, in order to increase attendance turned to cheap "Publisher's Clearinghouse" tactics. This series starts out at new college 1. This series is an amusing look at what is becoming an increasingly aggressive market. Collectively, these all show what a broad range of topics are covered in cartoons. This is true for any general theme, as is shown throughout this webpage.