desire

People new to Buddhism often conflate desire (chandha) and craving (tahna), and this is partially the fault of translators, but desire and craving are actually two different but closely related aspects of our psychology. Desire is a neutral term, and one generally has to have the desire to achieve a goal in order to achieve it, even nibbana (SN 51.15); whereas the Pali word for craving, tahna (literally 'thirst'), is something that's directly tied to suffering.

The second noble truth states that the origination of suffering is "the craving that makes for further becoming — accompanied by passion & delight, relishing now here & now there — i.e., craving for sensual pleasure, craving for becoming, craving for non-becoming" (SN 56.11). As Thanissaro Bhikkhu explains in Wings to Awakening:

Craving for sensuality, here, means the desire for sensual objects. Craving for becoming means the desire for the formation of states or realms of being that are not currently happening, while craving for non-becoming means the desire for the destruction or halting of any that are. "Passion and delight," here, is apparently a synonym for the "desire and passion" for the five aggregates that constitutes clinging/sustenance [III/H/ii].

Desire, on the other hand, can be skillful (kusala) or unskillful (akusala) depending on the context. The desire for happiness, especially long-term welfare and happiness, is actually an important part of the Buddhist path. Moreover, desire is listed as one of the four bases of power (iddhipada), which themselves are included in the seven sets of qualities that lead to the end of suffering (MN 103). The four qualities listed in the bases of power are desire, persistence, intent and discrimination. In Wings to Awakening, Thanissaro Bhikkhu points to this passage:

There is the case where a monk develops the base of power endowed with concentration founded on desire & the fabrications of exertion, thinking, 'This desire of mine will be neither overly sluggish nor overly active, neither inwardly restricted nor outwardly scattered.' (Similarly with concentration founded on persistence, intent, and discrimination.)

He goes on to explain that, "This passage shows that the problem lies not in the desire, effort, intent or discrimination, but in the fact that these qualities can be unskillfully applied or improperly tuned to their task." If we take a look at the exchange between Ananda and the brahmin Unnabha in SN 51.15, for example, we can see that the attainment of the goal is indeed achieved through desire, even though paradoxically, the goal is said to be the abandoning of desire. That's because at the end of the path desire, as well as the other three bases of power, subside on their own. As Ananda explains at the end of SN 51.15:

He earlier had the desire for the attainment of arahantship, and when he attained arahantship, the corresponding desire subsided. He earlier had aroused energy for the attainment of arahantship, and when he attained arahantship, the corresponding energy subsided. He earlier had made up his mind to attain arahantship, and when he attained arahantship, the corresponding resolution subsided. He earlier had made an investigation for the attainment of arahantship, and when he attained arahantship, the corresponding investigation subsided. (Bodhi)

So, in essence, desire can be beneficial in certain contexts, and one shouldn't be worried about the desire to do skillful things. Craving, on the other hand, is something that, by its very nature, conditions suffering through the way it encourages the mind to feed upon sensory experiences and either causes it to intensely cling to pleasant experiences or violently push away unpleasant ones. It may have helped us at some point in our evolution, but now it tends to do more harm than good.