A failing grade or too low attendance score, for a single required class does though. Granted it's possible to return and complete the credit but lots of people, for lots of different reasons, never do it.

Moving to a new state a couple months before graduation and the old school drags their feet on transfer papers will certainly make one miss graduating and not get a diploma. Illness is another. If you miss out on last quarter because of an illness you were hospitalized for. Don’t be so obtuse. Obviously if you sleep in and miss graduation day, you can still stop by the office and get your diploma.