Muscular Stupidity

Brawn over brains. Your character has dedicated his life to becoming incredibly fierce in martial combat, Your Strength or Constitution scores increase by 2 (Your maximum for those scores is now 22 or 26 if you have a level 20 barbarian). Because of this your character is incredibly stupid as they had not time for book reading, only combat. This will cause them to fail the most simple of intelligence checks, and will only be able to solve puzzles and riddles by accident (even with a high intelligence).