What do each of the effects mean when opening pack?

When you open packs sometimes one kuriboh will be shown, sometimes three, sometimes three then a big one. And when the pack itself is shown, sometimes nothing happens, sometimes a blue aura appears, sometimes a golden aura, sometimes a rainbow aura, and sometimes hyroglphics are shown and sometimes when you tap it your charecter thats selected at that time pops up with approval. Ive tried to peice together what means what but i caant figure it out, sometimes the yellow will show and i got all common and a rare, the rainbow would happen and all i got was a secret rare. For a while i thought the kuribohs meant the amount of new cards you got but my theroy was debunked rather quickly. I just waant to know when to be disappointed and when to be happy, please help me here.