Raga and dvesha are two notorious impediments in the path of a spiritual journey. Raga is attachment and dvesha is aversion. Vedantic scriptures tirelessly warn a seeker to guard against them. In a pair of verses 2.62 and 2.63 of Bhagavad Gita, Sri Krishna enumerates eight steps as to how attachment arises and leads to spiritual downfall.
2.62
ध्यायतो विषयान्पुंसः सङ्गस्तेषूपजायते।
सङ्गात् संजायते कामः कामात्क्रोधोऽभिजायते II
dhyāyatō viṣayānpuṅsaḥ saṅgastēṣūpajāyatē,
saṅgāt saṅjāyatē kāmaḥ kāmātkrōdhō.bhijāyatē.
When the mind dwells on sense objects, then attachment to sense objects arises. Attachment leads to a desire for the sense objects and the desire to anger.
2.63
क्रोधाद्भवति संमोहः संमोहात्स्मृतिविभ्रमः।
स्मृतिभ्रंशाद् बुद्धिनाशो बुद्धिनाशात्प्रणश्यति।।
krōdhādbhavati saṅmōhaḥ saṅmōhātsmṛtivibhramaḥ,
smṛtibhraṅśād buddhināśō buddhināśātpraṇaśyati.
From anger arises delusion and from delusion, memory loss arises. Memory loss results in loss of intellect and discrimination. With the loss of intellect and discrimination, one is lost. He loses everything.

Explanation
The world is full of sense objects and it is not possible for a person to shut the senses from being impacted by them. Yes, a seeker may try to avoid the sense objects. It may or may not work. In an earlier verse 2.60, Sri Krishna says that even for a wise person, the mind is susceptible to the vagaries of turbulent senses, not to talk of a seeker (emphasis added). The problem stems when the mind plays mischief by constantly thinking about sense objects. SwAmi Tadatmananda terms it the slippery slope. Unless it is arrested, there is a danger of free fall as it gives rise to attachment and identification with the object. In a later verse 2.67, it is stated that if the mind wanders in the sense-objects, then discrimination goes astray like a boat on water carried away by the wind. Attachment leads to desire in the form of emotional dependence. If the desire is obstructed or unfulfilled, anger springs. Now is the danger zone because anger causes delusion and the distinction between right and wrong is obscured. The person forgets whatever values he has learned and accumulated. His intellect stops functioning as if it has surrendered. He is prepared to commit adharmic actions in pursuit of the desire. A person whose intellect is destroyed has reached the bottom of the slippery slope. He is lost.

Remedy

What is the remedy to stop the downfall? It has to be dealt with at the time of dwelling on sense objects and prior to the threat from attachment. Suppressing the attachment is counterproductive. Vedanta does not approve of it. An effective method to negotiate dwelling on and attachment to sense objects is to understand the real nature of sense objects: they are impermanent and cannot supply continuous happiness. Vedanta is emphatic that sense objects are devoid of any happiness. If one desire is fulfilled, another takes over. In other words, if a person expects permanent happiness from sense objects, then it is self-deception. Obviously, such understanding is not a quick fix. It needs practice. Ups and downs will be there. Eventually, a sincere seeker should overcome attachment and progress on the spiritual journey.

 A doubt and clarification

It is not possible for a person in grihasta ashram ( family life) to be without any desire. In such a situation, a grihasta has to distinguish between binding and non-binding desires A binding desire is prohibited as it involves emotional dependence. A non-binding desire is without such dependence which means that the person remains satisfied if it is not fulfilled. SwAmi ParmArathananda gives the example of tea and coffee. Though a person has a preference for coffee, he remains satisfied when tea is offered. Thus the key is to convert desires into preferences.