SÄMST ELLER VÄRST?
Comparative and superlative forms of DÅLIG have two variant:
dålig - sämre- sämst
dålig - värre- värst

How do I know which one to use?

Question

SÄMST ELLER VÄRST?
Comparative and superlative forms of DÅLIG have two variant:
 dålig - sämre- sämst
dålig - värre- värst

How do I know which one to use?

Answer

Basically värre/värst is used to describe a deteriorated or worsened situation or state of something already negative, such as natural disasters or an injury..
Sämre/sämst is used to describe a deteriorated or worsened situation or state of something which not necessarily is negative like someones behavior or a song.