Being a dad means being your child's father. Not your child's friend. Dads who get this confused have confused kids.
Kakashi's kids saw him as the "fun" parent, Iruka was the "mean" one(Or as mean as Iruka can get), Kakashi let them ate junk food for all he cared, Iruka made them heaping plates of vegetables and tofu.
But the children never saw Kakashi as a friend figure. Kakashi was too much of a father for that. He may have more fun with the children than Iruka does but he was more willingly to tell his kids when they were about to do something stupid or idiotic or that had done in his youth.
He could give them cookies for dinner(And he does) one night and the next night lock them in their rooms for sneaking out with some random boy/girl. He knew when it was time to be a father and when it was time to be a "friend" he never mixed the two up.
And that is why his children respected him or as much respect they could give him when he was giving them a speech on how he was their father and not their friend while only wearing boxers stamped with smiley faces.
Author's Note:Gah! This one is too short and it did not come out right! This one was/is really hard. The next one is much easier to write. But this one came out horrible! I'm sorry, the next one will be my best(And hopefully longest) one! If not I will... I can't run a thousand laps in the snow or in non snow, so I will shovel my driveway!