In my first woodworking class, shellac was praised for its glow but warned for being brittle. Doesn't that mirror how we sacrifice durability for beauty in so many things?

Wait, is it just the coffee grounds by themselves? Because that might be the problem. Coffee grounds are what they call "green" stuff, like kitchen scraps, and they need to be mixed with a lot of "brown" stuff like dried leaves or cardboard. If you just pile up the grounds, they get really wet and dense and just grow mold. You gotta mix it all together and turn the pile sometimes so it breaks down right into dirt instead of turning into a weird science project.

Check your joints being uneven isn't always wrong. Some old school bricklayers leave them a bit rough on purpose to help water run off. That guy learned a messier lesson about giving advice while walking a dog though.