Risk is the optimal point here. Optimism implies hope, and hope is always linked to risk. Pessimism implies despair, and despair is also linked to risk. Hope comes from risks worth being taken, while despair comes from risks that weren't worth the effort. Risking is always vulnerable. It exposes us to both great triumphs and grave defeats. Gaming is a unique area to look at this phenomenon, which we see in all aspects of life, because there are many easily identifiable layers of risk.
First as Russ pointed out there is the risk of the newest game, hardware, community, etc. not panning out the way we hoped. It didn't match up with what our risking ourselves was worth to us. Even if we didn't get hurt, just being less then satisfied could be cause enough to not be as willing to risk as much in the future. The less effort we put forth when we risk the less we can be disappointed, however the inverse is also true. The less we can be elated when little effort is put forth.
This is also a core aspect of gaming in general. When we are playing games we are risking our avatars. Whether they be the hand and gun seen in an FPS, the legions of obedient soldiers at our disposal in an RTS, the custom designed and cared for characters of an RPG (especially MMO's), or even the level indicator and scoreboard of the Tetris screen. Risk is intrinsic to success in gaming. If you don't move forward you will never win and experience the end of the "hope" you started with.
Just as with life we cannot let defeat lure us into giving up and not risking. It always ends in shells of the people we could and should be. Now of course in gaming it's a bit easier. First off we don't actually fall down the pit of bottomlessness to our death like our on screen counterpart. So that is a safety feature that provides us with more confidence in our ability to risk. We know we won't actually fail. Beyond that there are always walk-throughs, and beyond that cheats if we decide they are wanted. (I personally never think they're needed, but either way want/need the point is they're available.)
This environment of a safety net allows us to find out that risking is worthwhile. And while there is no cheat sheet for life, perhaps seeing that the risk is worth taking in a game can remind us that risk is worth taking in real life as well. That is one of the reasons I game. At the end of the day I might not be employed at the moment, but I can kill a bunch of Zerg with my old copy of Starcraft, and know that risking yields rewards. There is hope. Always hope.