My question is, why is it that even though the title, description, and content are about a topic; the adsense ads sometimes are not related to the content?
Either because your content is poor or lacking in quantity, or there are few or no advertisers for your site niche.
Google is the number one advertising company to show relevant ads in your site.It will take some time to show good relavant ads in your site. But you should write good articles and follow the keyword density, so that you will get Good relevant ads.
Not enough advertizers on the topic, or simply because we should not care about which ads are being displayed since it varies from one user to the next, and just focus on producing content, let adsense work on the ads.
You will need to have enough content on the page to begin with text that is. And like someone said it does take a little bit of time to start showing relevant ads if you recently added or changed the google adsense code to the page. Otherwise change it up and add more text related to the post.
OR, your site is showing lots of interest based ads (based on search history of the user), and these are often much higher CTR so it's all good
Are you loading the same site everyday but not clicking the ads? Try another computer with a different IP. You will see different ads, most probably more relevant ads.