Comparative claims can be positive or negative, subjective or objective. But, in every instance, their main purpose is illustrative. A common example is when someone claims that a person or process is “as slow as molasses” (which, by the way, has a viscosity of only 5,000 to 10,000 centipoise [cps]).
In the world of assembly, however, it would not be surprising to hear assemblers and other plant workers say that someone or something is as slow as peanut butter (150,000 to 250,000 cps) or lard (1 million to 2 million cps). The reason is because many of the materials they need to dispense are this thick.