Epic Failures
If you don't want to use dice...
I spent an hour on SS team, quick start, trying to roll a five. I immediately rolled 2 1's in a row. Then a 2. Then a 3.
I spent another two hours trying to roll another five. I immediately rolled another one right after... Then a 3. Then a 6. Then a 1. Will I make it on the final turn?...
I ended up in canyon team mode.
The wonders of babies.
When flight was fairly new, when kamikaze did too much self damage, but when flight could own a lot of people.... I sacrificed one by accident. How? It was 3AM, I had stayed up all night to breed it and in my excitement of identifying it... I sacrificed it. Wonderful.
Working without Knowing
Early in the game, I had gotten a skill called "thunderstorm". I thought to myself, "I don't want give such a strong skill to a monster that isn't pure S! Only the best for me!" so I bred many A+'s and S's together for that wonderful, pure S.
But then, I found out fritz couldn't learn thunderstorm. Only epics [or legendaries, at the time], could learn advanced moves [which weren't stated before as advanced or not]. Good bye 400g+
The Terrible Realization...
... that most time I spend on this game is only talking. I never do challenges because I'm talking. I'm falling in ladder because I'm talking. I don't do anything. I don't even use any of my challenges [and 10 is a beautiful thing!] In fact, I question my Haypi Lifestyle.

Respect yourself enough to walk away from anyone or anything that no longer serves you, grows you or makes you happy.