trophies make me feel big, in the pants.
Hehe. In a nutshell (pun definitely not intended), that's what any trophy is for. For the PS3, the trophies are simply a way to show off how big your e-peen is. In real life, trophies are again a way to try and show off. That's all there is to it.
I would pay attention to trophies if they were earned through actual challenges. Most trophies are acquired through completing monotonous tasks, so little satisfaction is awarded.
For example, following are pointless trophies given to the player for simply playing the game:
Defeat first boss/level/mission (offers another trophy for each boss/level, even though these must be completed to progress through the game, anyway)
Play in an online game/match
Play X number of online matches
Collect a powerup
Equipped/used x item
Obtain X item/weapon/skill/etc (even though X item/weapon/skill is forced onto you as you progress)
Leveled up to level 10 (offers a trophy per 10 incremental levels, even though you will level up to 30+ just by casually playing through the entire game)
Discovered X area/region (x area/region is an area you must reach to progress in the game)
Kill 100 x enemies
Purchased/sold x items
Clock X hours of game time
Meet X NPC (even though you must meet this NPC to progress in the game)
These aren't challenges that warrant a reward. These tasks offer no sense of accomplishment. They add no replay value, as you will always get them your first play through. No bragging rights, there.
Trophies should be awarded for completing challenges, such as:
Complete game on X difficulty
Reach level X without losing a life
Collect all X items ("X items" being items that are not required to complete the game)
Complete every level with X rank
Complete level X taking no damage
These are simple, general challenges that can apply to most games. Each game should also have its own specific trophy challenges. For example, the following are game-specific challenges:
"Destroy the Spider Boss on Arachnophobia, without destroying any of its mini guns."
Ratchet & Clank All 4 One
"Use only Reflectors to destroy the generators in Phonica Moon's security tunnels. (2P+)"
Plants vs Zombies
"Stop the horde using only the Sunflower, Wall-Nut, and Chomper"
These are challenges of varying degrees. Trophies shouldn't be awarded for only the most difficult challenges, but they should not be awarded for simply progressing through a game.
The majority of trophies are freely given to the player. These "give away" trophies are grouped with trophies awarded for actually completing challenges, therefore I'm going to assume anyone who has a lot of trophies, has simply played a lot of games. I'm not going to assume they've accomplished any notable feats, even though they may have spent countless hours on some of the more difficult trophies.. which is unfortunate for them.