Success: While everyone had struggle against Ghetsis' hydreigon, I caught and trained a venipede into a scolipede for that reason and successfully defeated Ghetsis without losing any pokemon
Failure: I once sold a 1x31 heracross for a low price below 8k, It was a long time ago and I was a noob. Also, remember that shiny Meowth? Yea, I used 1 masterball on it, although It didn't have any risky move such as Explosion, Take down or Final Gambit e.t.c