Too many have been covered by others in far more depth, BUT
Adverts that use ridiculous imagery to serve a purpose.
My pet hate at the moment is the Cow and Gate (may not be Cow and Gate) baby milk formula.

"Your baby would have to drink this much cows milk in order to get the iron they need." Then a ten gallon drum of milk shown with the small disclaimer underneath; "Cows milk is not a good source of iron"

You may as well have a hod carrier lumping a full load on the table.
"Your baby would have to eat this many house bricks in order to survive." "Oh, bricks are not a good source of sustanance."

Don't even get me started on Injury Lawyers for You. I'd call them up to tell them their advertising totally discourages me from ever using their service. (The edited polite version shown here.)

Rant over. For now at least.
( Blind Meach Cautiously optimistic, Sat 10 Apr 2010, 10:45, 3 replies)

I can see both sides of this
On the one hand, yes, it's sensationalising it to a degree.
BUT cows milk is what many people would think of as an alternative to follow on milk, so assuming that their medical advice is correct, it's an important message, and comparing to a valid competitor
( Tedium Alduce me to interlow myself., Sat 10 Apr 2010, 11:48, closed)

Oh I agree entirely,
To market something you need to grab attention. But this is taking it to a level plumbed by only the most dire agency.
It may also be the case that there are other sources of iron in a healthy diet.
( Blind Meach Cautiously optimistic, Sat 10 Apr 2010, 12:16, closed)

Seeing as babies have a large store of iron at birth,
milk is not supposed to provide much of it. That's where learning to eat solids comes in...
( Colonel Boris "...a desperate Buzzfeed imitation...", Sat 10 Apr 2010, 13:01, closed)