for me, I'm more frustrated with zero drops. As long as I got something, it's not a waste for me
They're frustrating in different ways for me. Getting nothing is obviously annoying, but getting a lone Demon Crystal is just, "Oh, you got my hopes up with a gold treasure icon for something trivial."
Personal favorites, by game:
Millennium War Aigis (RIP): Liana
Girls Kingdom (RIP): Iris
Dragon Tactics: Memories (RIP): Diske
Brave Girl Ravens xR (RIP): Francette
...Most of the games I play on Nutaku end up getting taken down. Hmm.