America isn't the most punctual culture, but there are plenty of cultures that are much more casual about lateness, including some Middle Eastern, South American, and African cultures. Most Americans brush off as much as 15 minutes of tardiness, but in some cultures, 30-60 minutes isn't uncommon. The German student who consistently shows up a few minutes early may be annoyed that fellow students show up a few minutes late, but a South American student who shows up 45 minutes late is going to be immediately branded as lazy or unserious.