Try figuring this one. You state "Now however if there is one or two characters I really like I might overlook my distaste for it", indicating that you check without a definition of frequency, and then "more than likely I won't read the GM made characters at all."
A backwards system, wouldn't you say, when you check for characters you might really like - an open course where you're seeing what's up and then dismissing accordingly if it's boring garbage - but then say that usually you don't even give that benefit of the doubt in the first place. By that logic, most of the time you don't even check for the premade characters you may really like.
You are assuming things are read in the order you say. Now try the intelligent way.
Read the plot summary.
Find premade characters.
Decide if the plot is worth it.
If the plot is worth it, read the characters.