The first rule of any enterprise is to figure out what your customers want and give it to them. A Dungeons & Dragons game is no different. If your players just want to kill monsters and not think too hard, they're not going to be happy with a subtle murder mystery or combat-light court intrigue. Similarly, if your players love to immerse themselves in their characters and enjoy the play-acting more than anything else, they won't be happy if you present adventures that don't give them opportunities to talk to the creatures and characters around them.

Most players fall into one of four basic categories:

• Actors: These are players who enjoy roleplaying for its own sake. Extreme actors would be just as happy to play D&D if it had no rules at all. Players who like this style of play often choose the bard, ranger, and rogue classes. They like adventures that have lots of opportunities to talk to nonplayer characters (not just villains and monsters), and they tend to dislike adventures that offer nothing but combat encounters.
• Puzzle-solvers: This type of player loves figuring out riddles and challenges in the game and would also be just as happy to play D&D without rules. They often play clerics, rogues, and wizards. Puzzle-solvers don't mind combat encounters, because beating tactically challenging encounters (such as archers on a castle wall) is solving puzzles of sorts. They like adventures that offer chances to solve riddles and puzzles as players at the gaming table, and not just by rolling dice as characters in the game.
• Hack-and-slashers: These are players who just love to fight and beat up monsters. The bigger the fight, the happier they are. Hack-and-slashers live for dishing out the damage, and they're inclined to like the rules, because the game rules help them figure out how much damage they can deal out. Hack-and-slashers often play barbarians, fighters, and sorcerers. Obviously, they like adventures with plenty of monsters to fight, and they don't like adventures that involve too much talking.
• Competitors: These are those players who play for the thrill of winning in whatever form it might take. They're happy to fight big fights and win, but unlike the hack-and-slasher, they're just as happy to win by doing roleplaying or solving tough puzzles. Competitors tend to be heavily engaged with the rules, and they don't like to throw out the rulebooks. You can throw a variety of challenges at a competitor, and he or she is happy. Competitors often play clerics, fighters, and wizards.

Now, here's the tricky part: Odds are, you have players of more than one type in your game. One player may like roleplaying, another might like combat, and a third player might be interested solely in beating the game. The best way to keep everybody happy is to simply alternate the types of encounters to cater to your players' various interests. Intersperse roleplaying encounters with combat encounters and challenge encounters, and you can make exciting adventures that feel varied and fresh where everybody gets the game he or she wants at least some of the time.