Q:

I accepted an answer that wasn't the best

I recently posted this question and got into a discussion with someone who clearly had done more research and taken the time of his busy day to explain things to me. 
That answer did help me (even more than the answer I accepted) but It didn't explain why I couldn't do what I wanted to do.
The other (accepted) answer is just a one liner which when I read it was so obvious that I felt rather dumb, but it did really help with my problem and showed me why I had my problem. 
Should I change the accepted answer?
Or should I maybe ask the guy who gave the more exhaustive answer to add a note to his answer and then accept it?

A:

Should I change the accepted answer? 

It doesn't matter which answer you accept.  You may upvote both, since they were both useful.  

Or should I maybe ask the guy who gave the more exhaustive answer to add a note to his answer and then accept it?

No.  That is doing a disservice to the other author (making their answer obsolete).  It is OK for a question to have multiple answers, which address the issue in different ways.  Time will tell which post future readers find more useful.  

