Quest

A quest is a task assigned to you by an NPC for some reward. Quests have no impact on the overarching storyline; however, through the dynamic quest system, quests can effect other quests and explorable areas, as well as add depth to the world of Guild Wars.

An NPC with a quest to give will have a large, green exclamation mark (!) over his or her head. Speaking with that NPC will allow you to hear the quest and choose whether to accept or decline. Accepting the quest will add it to your Quest Log. Declining the quest (or abandoning it later via your Log) brooks no penalty: you can always reacquire the quest by speaking with the NPC again.

Quest Categorization
Some quests are marked in-game as primary quests. Besides primary quests, there are no other official categories for quests. However, there are many commonly understood categories of quest.

Primary Quest
In pre-Searing, quests that propel you towards joining the Academy are marked as primary quests. In post-Searing, primary quests are used to lead you from one mission to the next. Anytime a completed mission sends you to a non-mission outpost, there will be a primary quest to get you to the next mission.

In both cases, primary quests generally do not have many inherent rewards. The purpose of the primary quest is to advance you in the game, not advance you monitarily.

Primary quests are identified by the green text "(Primary Quest)" next to the quest name in your Quest Log.

Skill Quest
Skill quests include any quest which gives you a skill or skills as part of the reward. These quests are the most popular to do, as the rewards for most other quests aren't worth the trouble for most players.

Skills rewarded by quests do not cost any skill points, providing an added incentive for completion. Before reaching Lion's Arch, skill quests are the only method of acquiring a variety of skills.

Profession Quest
Profession quests include the six quests in pre-Searing Ascalon that allow you to get a secondary profession and the six quests in the Crystal Desert that allow you to change your secondary profession.

All profession quests grant the basic skills of a profession. Pre-Searing profession quests grant the skills before you finish the quest, allowing you to sample each profession before settling on one. The Crystal Desert profession quests grant the skills upon changing to the secondary profession for the first time. In all cases, you cannot use the skills granted if you change your secondary profession away from the profession that granted the skills, though you do retain the skills should you change back.

Attribute Quest
Attribute quests grant you extra attribute points to use. These quests increase your power in a very direct way. Every player should seek these out and complete them.

These quests are among the most difficult in the game.

Other
Quests that do not fall into any of these categories are just called quests. They generally reward you with some experience, some gold, and a few items, though the exact mixture of these three rewards vary depending on the quest.

Quest Rewards
Quest rewards include experience, gold, items, skills, skill points, and attribute points. Most of these act as you would expect. However, quest items are fundamentally different from normal items. First and foremost, they cannot be salvaged. Secondly, they have a higher value than a comparable looted item would have (often 2-3 times higher). In general, you should not use weapon upgrades on quest items, as you cannot get them back should you change to a different weapon. Most people sell their quest rewards immediately, as very few are worthwhile enough to keep. However, in the early game, some rewards are useful, as they can be better than the equipment that is dropped.