Zabbix trigger expressions provide an incredibly flexible way of defining problem conditions. If you can express your problem using plain English or any other human language, there is a great chance it could be represented using triggers.
I’ve noticed that even experienced Zabbix users are not always aware of the true power of triggers. The article is about defining problems in a smart way so that all alerts generated by Zabbix will be about real issues. No flapping, no false alarms any more. Interested?