Characters appear for a few episodes, then disapper, and then reappear many episodes later.
In The Wire you generally have to wait several episodes for minor plots to resolve, and until the end of the season for major plots to resolve. Some subplots last for years. Characters appear for a few episodes, then disapper, and then reappear many episodes later. Thus, when you get to an episode of The Wire, you may be unsatisfied, but you will have to wait.