My very first one was Uncharted. However, still being new to the system I didn't realize they had to synch with the server. After beating the game I saw a commercial for the Infamous bundle at Best Buy. My genius self realized I had a 2 year replacement on my ps3 from Best Buy and proceeded to box it up and drive to the store. I then proceeded to tell the clerk my system kept freezing and I wanted to trade it in for another. Well, the 100 price cut had recently occurred so I got to trade it for the infamous (and I believe killzone) addition and got 100 in store credit. I laughed as i drove home with a new ps3 and 2 new games and 100 dollar BB gift card for my uncharted bundle and thinking I was so slick...
Well, hooked it up and signed in and noticed that my platinum, dynamite and crushing trophies were gone. It took me an hour or so to realize that I had unplugged and returned the last system without syncing my trophy list. To this day I am still missing those three trophys. Goddamn young self.
EDIT: Since, I have plats in both Infamous games with 100% in Festival, Modern Warfare, Terminator Salvation and Uncharted (just can't prove it)