You can't hide anything from your dentist or your mechanic. They can tell that you've been lax on that regular maintenance so there's no point in lying. You can see what mechanics consider to be some of the sorriest and strangest things they've ever had to work on in the following list (sourced from r/justrolledintotheshop). Be sure to vote up your favorites and seriously, go get that oil change.
1. The Computer Says It's All GoodPhoto: u/Trip_Jones / Reddit
2. Looks A Little OffPhoto: u/thegirlthatmeowsalot / Reddit
3. It's Not Meant To Look Like That?Photo: u/domster22 / Reddit
4. That's A Bad Thing?Photo: u/izhevsk762 / Reddit
5. About To Pop!Photo: u/Mandersonned / Reddit
6. What Is Happening Here?Photo: u/Swifty3174 / Reddit