What is the worst medication you've ever had to take? "Worst" can mean many things: bad tasting, debilitating side effects, frequency/dosage/timing inconveniences (e.g. like take every 3 hours even when it means waking up throughout the night). It might even mean least efficacious and you ended up taking something you didn't need.
Anecdote: my wife's grandfather was in a nursing home and one time when we visited the pill cart stopped by and unloaded a small bucket of meds on him. When we asked the nurse what they were for she refused to tell us. Long story short: we ended up rattling some cages and found out later he was being given pills for things that he had no need for whatsoever!