Slight correction - polyunsaturated fats are not ‘baddies.’ These are essential for brain function, cardiovascular health, cell growth, etc., and are usually underrepresented in typical American diets.
FYI there’s nothing special about microwave popcorn. You can get the same results, save money, and skip the PFAS by buying a jar of popcorn kernels, dumping some in a brown paper lunch bag with some oil and salt, and microwaving it on high for 2-4 minutes. You don’t even need a bag, you can do it in a covered bowl.
The baddies are the saturated ones, i.e. those where not all carbon atoms in the carbon chain have only single bonds.
You are partly correct. Saturated fats (and trans fats) are the baddies. Saturated fats have single bonds for all carbon atoms in the carbon chain. “Those where not all carbon atoms in the carbon chain have only single bonds” are referred to as being unsaturated. Most unsaturated are not “baddies,” except of course generic trans fats formed by hydrogenation. But there are even some examples of polyunsaturated fats where one or more double bond is trans, such as CLA’s and SPM’s that are actually beneficial.