I mean, they make poor-tasting coffee. That seems like it's the worst thing of all.

When you roast and then grind coffee, it releases carbon dioxide. If you seal it up after processing, it will usually inflate a bag; that's why most coffee bags at the grocery store have that little one-way check valve in the bag itself.

The only way to keep coffee from offgassing is to let it go stale first. That's what they do to most coffee that used to come in metal cans. They have to do the same thing to the pods. At best, your coffee is pre-staled and only gets worse from there.

Then you have all the stupid non-recyclable waste. A plastic pod that gets boiling water run through it, I'm sure that it's leaching a fun mix of chemicals into your coffee. There is also a paper filter in there and a foil top. No way to recycle these things unless you separate all three parts and the plastic body weren't made of unrecyclable frankenplastic (aka #7).

Fuck those pods and any twat who is too lazy to make a damn cup of coffee without one. Get a cheap ceramic pourover and a box of #2 filters. Grind coffee, boil water. add grounds to filter, pour hot water. The only waste is a soft paper filter and some grounds, both of which can be easily composted if you like.