Badly designed airports can also prove a real bugbear to the traveling public – in particular, the apparent need to fill as much floorspace as possible with expensive stores. If even one or two of these were removed, there would be more room for waiting passengers to sit down.
An article in U.K. newspaper The Guardian has even suggested that air travel exposes divisions in status. Essentially, rich people enjoy a much better flying experience, skipping lines and enjoying first class travel. Consequently, people who witness this feel worse because they contrast their own discomfort with what they see.
Perhaps the biggest complaint from regular flyers, though, concerns other passengers. Unfortunately, when humans are put in stressful, cramped conditions they tend to notice the personal habits of other people all the more acutely.