Perhaps I'm mad? I really like Drupal and what it can do for me!
Just to balance the haters a bit. Yes, Drupal is a complex beast, I reckon it takes three to four years of building sites with it to really get to know it properly. The main tasks being to learn "the Drupal way" and to learn which contributed modules are worth using, and how they work.
However, if you're willing to invest time getting to know Drupal then it can be a very powerful tool to build quite complicated database-driven web applications. I started with Drupal 5, which was not nice and which required lots of custom code to be written. Now with Drupal 7 I find I can build pretty comprehensive sites with hardly any custom code at all.
Oh, and I run Drupal on a VPS with SSD storage and find that it runs plenty fast enough even with many dozens on enabled modules (I will agree that with spinning rust storage it can be a little slow, you do need a half-decent server). There are lots of caching possibilities in core and with external caches if you really need them, and Drupal 8 (not yet ready for complex sites, several useful modules are not yet fully updated for 8) has big improvements in how content can be cached efficiently. Drupal works fine for governments, universities, and record labels, so there are plenty of big users who find the performance is not a problem.
As with any software, it's horses for courses. Creating a blog with Drupal is quite a lot of work, WordPress does that sort of task much better out-of-the-box. But for more database-like sites Drupal beats WordPress easily. You can of course resort to a basic framework, or write all your code from scratch. Drupal is simply a powerful high-level system for building database-driven web applications, where all the standard boilerplate stuff is already done for you.
I suspect the haters here might be people with Computer Science degrees. Mine's a Mechanical Engineering one - I'm more of a systems analyst than a coder. I don't care so much about the clean aesthetics of algorithms, I just like stuff to work as a useful tool to get the job done.