The lake of fire is a very emotive subject to some. The fact that God can have such a place seems alien to them and yet he did not make it to put people in it but made it as a warning, a deterrent. Unfortunately if people do not want to listen then God can't be held accountable for their ignorance and rejection.
The actual manifestation of this lake of fire is not necessarily one of a physical lake burning with brimstone. It is after all a spiritual eternity. The lake to which they are tormented is also translated as a flame. The eternal torment given out after the White throne Judgement is one of a thirsting, a spiritual hunger that can't ever be satisfied because they are out of the reach of God. Today we see a longing for some sort of spiritual high by people, because we are by nature spiritual and need God. This is the eternal torment, the need for spiritual food to sustain our soul, in the darkness of Godlessness. It will be like being on the brink of death from thirst or hunger but never actually dying. Alone, and with your thoughts it will be a terrible place.