103 recursive SQL queries on a single page can perform "fast enough"
if appropriate indexes are in place etc. That's not the problem.
The problem is that such programming style makes sites that
don't scale as number of users of a particular page grows.
Your notifications page is a good example. It is probably not a page
people visit very often: a *regular* user perhaps visits it a few times
a year.
Something I've seen happening again and again with such pages is this:
After years of use without any problems, an admin sends a newsletter
to all registered users:
TIPS AND TRICKS
Did you know? You can manage all your email notifications from one
place. Just visit http://path-to-the-notification-page ...
A few hundred people click on the link within a few minutes time. Your
site goes down.
