The categorical imperative

Immanuel Kant (1724-1804) posits the categorical imperative as a means to assessing ethicality. In part, the principle demands that its subscriber’s only act in such a manner that they can expect someone in a similar predicament would act or behave. Is this an oversimplification? Do you have a practical example of its application, i.e., how has it been used or abused? Evaluate the two aspects of the imperative to aid in your response.