Drupal offers some choices between performance and flexibility. There are heaps of recommendations for increasing performance and they are almost always applicable only to high volume Web sites where you have good control over the server and you have a very small proportion of your visitors logged in. Everyone else has to fight for performance from the ground up through the Web design and coding.
Lets look at some problems and the decisions you might make to reduce the overheads.
Use Views for fast development but slow performance
Views is a list writing tool gradually growing into a report writing tool. The main advantage of Views over competing products is the ability of Views to create both pages and Drupal blocks. To do anything else, you have to add on other modules. A typical Views installation has lots of add-on modules filling the immense gap in the Views system.
Some of the add-on modules are separate for a reason, they add option output styles you might not need. Views data export is an example. Some of the other add-on modules add really basic functionality that should be included as standard. Some of the functionality limitations are also related to Drupal 7 missing some basic functionality.