Because I adore Dawn Summers, the second most hated teenage character in genre TV history, I was willing to give Wesley a chance this time.
... does that mean Adric is #3? Although he was the first one, chronologically. (Not sure how familiar you are? Adric was one of the 5th Doctor's companions, and honestly not that bad. But he was a fairly accurately portrayed teenage boy - often moody and contrary, besides being smart - so he was intensely disliked.)