The Mattress Problem is a term used to describe the difficulty of finding a mattress that is both comfortable and affordable. The acronym SAG stands for 'sagging, ' which is when a mattress loses its shape and becomes lumpy over time. LUMP stands for 'lumpiness, ' which is when a mattress has an uneven surface due to poor support or inadequate padding. Both of these issues can lead to discomfort and a lack of quality sleep.