I don't know what commercials for children's cereal is like now, but looking back when I was a kid, they sent some questionable messages.  There were a lot of weird issues of ownership and, quite frankly, selfishness.  Kids were always stealing Lucky the Leprechaun's Lucky Charms and stealing isn't cool.  They could have at least, like, asked.  Then Barney was always trying to steal Fred's Fruity Pebbles.  But to be fair, Fred was kind of a dick about it.  Barney would dress up in all these disguises and Fred was happy to share his Fruity Pebbles with random strangers, but the minute he found out it was actually his friend Barney he'd flip out and chase him around and stuff.

But the one that pissed me off the most when I was a kid was the Trix rabbit.  All he wanted was some Trix and those mean kids would never give him any.  He was always just about to have a taste when some little punk would grab the bowl out of his hands and be like "Silly Rabbit.  Trix are for kids."  When I was in grade school this struck me as the height of injustice.  If I ever met the rabbit, I would have shared my Trix with him.  

I remember one time they had a campaign where you could vote whether or not the rabbit would get to try some Trix.  You'd better believe I got on top of that and voted yes.  From what I recall, the "yes" votes won and when it came time for the rabbit to get his Trix, I felt vindicated.  He took a big bite and was in heaven because he finally got the only thing he ever wanted, but then he woke up and it was all a dream and some jerkoff little kid was laughing in his face saying "Silly Rabbit. Trix are for kids!" 

I guess Trix was trying to prepare us for a lifetime of disappointment or something.