Let opponents beat that sentiment out of him.
In my limited expirience, she seems to be a pretty good counterpick character against most people who don't have targeted gapclosers and aren't mages (not that she has a general weakness against mages, I just don't see her winning against any of the mages that actually go top).
Unfortunately, that's a pretty limited selection of characters at the moment, singed, garen, maybe malph if she can crush him pre-6.
Let opponents beat that sentiment out of him.
Unfortunately, that's one of those things where it's very difficult to draw a clear line between doing it and losing because you have to recognize it's delaying your build resulting in the opposing AD carry doing more DPS then you in teamfights, and doesn't give you a significant enough advantage in lane to justify the delay.
Somebody whose conscious enough of the implications of builds to notice this won't make this mistake in the first place.