The large number of agencies and agency officials is the result, and possibly the cause, of, in some situations, a large amount of services and regulation. At work, you are subject to federal and local laws concerning discrimination in the workplace. Agencies exist to deal with this issue as well, such as the federal Equal Employment Opportunity Commission.
Your safety and that of your coworkers is regulated by the Federal Occupational Safety and Health Administration, as well as by local officials. Under federal law, you are entitled, with certain exceptions, to receive overtime pay and a minimum wage. Other federal laws concern employer-provided health insurance and retirement benefits. You may also have a right to form a union at work. The National Labor Relations Board is charged with enforcing this right.
All of this regulation is not free. Your earnings are taxed. At the federal level, the Internal Revenue Service is responsible for collecting a portion of your earnings; state and local agencies will collect income taxes as well. Little activity today has no connection to the administrative state, and, therefore, administrative law.