The lack of Database Abstraction in PHP

Unfortunately, almost none of the most popular PHP software supports other databases than MySQL (with MediaWiki being a notable exception - it supports Postgres). When you're used to programming in Ruby, multi-db compatibility is something you just take for granted after a while, because of the excellent ActiveRecord and DataMapper projects. In PHP however, this is a real deal breaker. I don't know if its a cultural problem or a library problem. I did look at Propel some time ago, but honestly the Java-esque XML configuration and over-complex API turned me off real quick. If someone could come up with something better, maybe even WordPress will support SQLite and PostgreSQL one day...