Believe it or not but there is actually controversy over whether or not you should optimize your ads.
The fact is that people dislike advertisements, they have also been made to distrust Internet advertisements because of rampant use of invasive ads and drive by downloads of adware, spyware, or even viruses.
Opponents of optimization see the act of optimization as tricking people into clicking on your advertisements, this is not true. Unless the person is uncontrollably clicking their mouse they will not accidentally click on anything. If a person clicks on a PPC advertisement it is because they read the title, they read the text, and it interested them. They may not have realized it was an advertisement but that is irrelevant because the ad is safe, the search engines police the behavior of those who advertise with them, and the person was interested in it. If someone is interested enough to click on a link then surely it cannot be so bad that they did click?
When you're optimizing your advertisements you are not tricking people into clicking on the ads, you're merely tricking them into reading the ads. Most people have a prejudice against ads and have trained their eyes to ignore them, you're simply overcoming their prejudice. Once the visitor reads the ad whether they click or not is dependent upon if they felt the content of the ad compelling or not.
Besides, this is your livelihood, and it costs you time and money to run your website, you deserve to profit off of it and visitors who deal with advertisements on billboards, TV, in the theatre, on the radio, in books, magazines, and newspapers, should not be offended by advertisements on a website.
So, optimize away, no user is going to inadvertently end up on a site they are not interested in, and all you're doing is making sure the ads get read. Do that and the clicks will take care of themselves.
For more on this issue see this blog post.