Why is life not a bed of roses?

The idiomatic expression "a bed of roses" refers to something that is beautiful, pleasant, or comfortable. In many ancient cultures, rose petals were strewn in the path of an important person, to show their high status and to show affection for them. While life can indeed have good days or good times, it also has problems and struggles and sadness. We cannot realistically expect that everything will always be beautiful and pleasant, even though we might wish it to be. Thus, we cannot honestly say life is a bed of roses.