Yeah, IV's, yeah. To further your point about those jerks... look at this! This is a croagunk I bred to use on ma team, and let's look at its pretty decent IVs (not all perfect because I am too uncaring).
31 speed? Frig yes! 25 and 25 for defenses? OK, not too concerned, but me likey. Wait..... 8 FRIGGIN ATTACK?! Potentially his most important stat has the lowest IV? How rude. So I figured I would try again, and started breeding again. But... I wanted a specific nature, and ability, so it was going to be a pain.
Though, the everstone on the mother pokemon is supposed to give a 50% chance of having the same nature, right? Convenient, since that croagunk is female. So I had my croagunk and ditto get busy and after something like 75 eggs (seriously...), and not a SINGLE ONE of them with the right nature, I just gave up. Bah.