Well desire is certainly better than tamasic inertia, but it need not be a mad desire. Desire restrained by the sattwic mind, a discerning reason, balance, moderation, not being too selfish is itself an excellent preparation for spiritual life. It may even be said that it is even impossible to jump from a life driven by mad kick of desire and ambition to the spiritual without passing through this stage of sattwic balance. Those who try this tend to lapse into tamasic inertia from time to time. The progress through ambition is limited and often bounces back. It is a horizontal progress in terms of quantity but at the expense of quality. Try taking up a work in which you feel inwardly happy and interested. Earn money for living but do not live for earning money. Aim for success and learn from failures. Practice moderation in all you do. This is the missing step you need to take between mad rush of desire and the steady path of spiritual progress.
Affectionately,
Alok Da