I always really liked Sierra's Police Quest series, but it was really quite extraordinary how they could sometimes manage to screw up the endings. Police Quest 4 (admittedly, the worst of the series) in particular comes to mind - you spend the first 95% of the game working on a great, realistic police investigation... and then, in order to catch the guy you're after, you are required to catch a stray dog using a piece of rope that you could find (but probably wouldn't even notice) in one of the earliest locations in the game. Argh. And then, do you get to capture the murderer using any kind of conventional police tactics? No, you gotta use a lighter and an aerosol can to improvise a flame thrower. Stupid, stupid, stupid.
In general, though, I found adventure games pretty bothersome. Most adventure games simply required such bizarre logic that I couldn't be bothered solving them on my own. I loved games like the Monkey Island series and such, but I always played with a walkthrough handy to get me through the toughest puzzles. It's a total waste of time when, in order to finish a game, you have to think
exactly like the guy that designed it.
And that's why I really loved Loom. Loom is one of the two (two!
) adventure games that I was able to finish without any additional hints. Yeah, sure, a lot of people complained about Loom being so easy you could finish it in a few hours - but I don't see how a game is made better by forcing the player to walk in circles for five hours just to figure out how to solve one puzzle. That's not gameplay, that's a waste of time.