a. The darker the color of red wine, the stronger aftertaste... almost bitter if I do say so myself.
b. Smoking a cigarette not only gives you bad breath and odor, but a leaves a different aftertaste depending on your cigarette (sometimes minty).
c. Regular, clear, plain water, when drunk, you will notice does not have an aftertaste.
d. Cut open a lime and suck out the juice, that taste you experience after you're done with it, is what is essentially called an aftertaste.
e. When you vomit or puke, you will notice an acidic and nasty taste. That is an aftertaste, that no one likes.