Guru, in sanskrit literally means heavy - heavy in their instructions to bonded souls, and heavy in that the guru does not budge away from the Lotus feet of Krishna.
When the guru speaks words which cut though our falsities of this world, that feeling is not very satisfying to the heart. But a person who is sincerely seeking the truth will acknowledge his unpleasant feeling and transform his heart. A person who is not sincere in order to avoid unpleasantness will brush those heavy words aside and continue with his ways. Such unfortunate people can never understand God no matter how much they chant, study scriptures, visit Holy places and or perform charity. What to speak of those who take shelter of false gurus?
I come across people many times who think Krishna consciousness is not practical, or only practical up to a certain level. Such people most likely approach Krishna for punya karma, morality or spiritual entertainment. Deep inside their hearts, they do not have the desire to give up their independent thinking and independent desires. Such people can never understand God!
Therefore the only way, one can understand God and be God conscious is to accept the heavy words of guru whole-heartedly without speculation and have faith that these heavy instructions can be followed at all times regardless of time and circumstance. The faith to follow instructions without deviation can be cultivated gradually over time by the sincere aspirant of the truth.
Srila Prabhupada is one such guru with heavy words and is one such disciple who emulated guru bhakti to the world without deviation. Below is an example of his heaviness in terms of instructions to his disciples. A sincere soul will be delighted to hear such instructions where as a frivolous soul will feel sadness reading it.
In a place made for misery, he told us, only the rascals try to make adjustments for peace by material arrangements. "They are mudha. It is not possible. Krsna has made it suffering. How you can become happy here? But these rascals will not understand. Within the suffering they will try to become happy. That is not possible. The toilet room he wants to make a Deity room. How it is possible? That is not possible. Therefore we should be careful not to make a friendship with our restless mind. Rather, it should be beaten with shoes and a broomstick and kept under control. - Srila Prabhupada- From "A Transcendental Diary Vol 5" by HG Hari Sauri Prabhu
For an untrained person, these words would be offensive. Prabhupada is comparing this world to a toilet and people who are trying to be happy in this world as rascals and mudhas (fools). Toilet, rascal and fool is not politically correct by modern day standards. If this world is a toilet, then all things of this world we consider sacred mainly wife, husband, children, relatives, money, house, job etc are also toilet.
Toilet means two things. (1) it is a place to shed our dirty nature (2) it is a stop gap place - finish your business and leave. So in that sense, this world, relationships and possessions are considered an impurity as it is materialistic and also temporary. In such a temporary material setting, what is the business of a pure spiritual being? From the vantage point of the pure spirit soul, he should finish (rather give up) his material business and depart to the eternal spiritual world where there is no misery.
So yes, on the surface Prabhupada's words can be heavy but an intelligent person will dig deeper to find the meaning behind his compassionate words. Such a sincere individual will take shelter of that compassion, will follow the instructions of Prabhupada, will achieve liberation from the shackles material bondage and eventually meet Krishna face to face.
This is the only way - there is no other way!