PHP is not OO (well, not at the time of writing)
PHP is a functional, procedural language, that the concepts of Object Orietation (objects, methods, etc) can be applied to generate standardised functionality and procedures. Later versions of PHP will be (and already are) more and more object oriented with obvious performance enhancements in terms of speed and reuse of code and data.
It took me a while to understand the advantages of the OO methodology and concepts, but seeing it and using it everyday generally help you to learn anything.
$d = new Dog();
I understand it now, but it took a while. Once it clicked there was no going back.
For a while I was anti-frameworks, feeling that they are over-complicated and unnecessary.
Some still are, especially some PHP ones.. ..but I am beginning to see their relevance in the great application stack hierarchy. I have even started using one myself now (not a PHP one), which is a shame, because now I think I owe @houdmont £5.
Frameworks are like buying a complete DIY toolbox. They are packed full of tools that you don't have to use, unless you want to. You may use some tools all the time, while others may never get used. This is a frameworks 'raison d`etre'. Use the bits you need.