If you program for a nontechnical audience, you find yourself at a high risk that users will not read your carefully worded and enlightening error messages, but just click o
Unless you can provide the user some simple work-around, don't bother showing the user an error message at all. There is just no point, since 90% of users won't care what it says.
On the other hand If you CAN actually show the user a useful workaround, then one way to force them to read it is make the OK button become enabled after 10 seconds or so. Sort of how Firefox does it whenever you are trying to install a new plug-in.
If it is a total crash that you cannot gracefully recover from, then inform the user in very layman terms saying:
"I'm sorry we screwed up, we would like to send some information about this crash, will you allow us to do so? YES / NO"
In addition, try not to make your error messages longer than a sentence. When people (me included) see a whole paragraph talking about the error, my mind just shuts off.
With so much social media and information overload, people's mind freeze when they see a wall of text.
Someone once also recently suggested using comic strips along with whatever message you want to show. Such as something from Dilbert that may be close to the type of error you may have.