Tee time intervals are the single biggest variable a course controls, and most courses get them wrong on the weekend. The math is brutal: shrink the interval to fit more rounds in, and you guarantee a backup that compounds with every group.
Why 8-minute intervals fail
A par-4 with average pace takes a foursome about 14 minutes to complete. Send a group every 8 minutes and you've created a 6-minute deficit, every hole, for every group. By the 7th hole, a Saturday morning tee sheet has become a parking lot.
What works
10-minute intervals on weekdays, 11–12 on weekends, with a built-in gap every fifth group to absorb the chaos. Most well-run public courses have figured this out. The ones that haven't are usually the ones you're complaining about.
What you can do
When you book, look at the tee sheet. If groups are stacked every 7 or 8 minutes on a Saturday at 8 AM, plan for a long round — or pick a different course.