The third of the four thoughts is the shortcomings and suffering of samsara. Coming to a proper appreciation of the suffering of samsara does not entail pessimistically interpreting every happy event as miserable. On the other hand, we do not want to go to the other extreme and cover up the suffering of samsara by referring to the future with words like “full of brightness”, “full of hope”, or “a radiant tomorrow” . What we need to do is squarely face the reality of cyclic existence and assess in a very objective manner whether this cyclic existence is in fact characterised by suffering or whether it is characterised by happiness.
Depicted from "Guide to the Four Preliminary Practices 2 - Part 27" April, 2015, Vancouver, Canada