human nature

i'm not one that's quick to attribute every (or any) negative or undesired behavior to "human nature." i think that too often, people use that as an excuse to be lazy and not allow the power of the Spirit of God to overcome the failings of humanity. (we've been granted victory over sin--claim it and be adapted to it).
but, i've been challenged in my perspective this week.
my 4-month old son has been granted permission from the pediatrician's office to begin eating cereal. for those of you who've been through this before, you know that's a big deal. for those who haven't experienced it, it's a big deal.
well, as expected from my genius child, he does really well with the spoon and swallowing. the problem is that we can't shovel it in fast enough for him. after about 10-15 bites, he starts to get angry and impatient.
so, is impatience wired into us? i can't imagine that he's old enough to have developed that yet. (give him at least a few more months before i'll admit that he's picked it up from me.) so, where is the line of nature and nurture?
on a tangent note: 4-months old getting angry is actually quite funny. he's actually trying to yell; he's not screaming or crying--pure anger. it's hard to be serious and comforting while holding back the giggles from within.
maybe it's a part of us or maybe it's learned. either way, it's our challenge, opportunity and responsiblity to allow God to help us overcome it.
Dear Lord, teach me patience and let me demonstrate it to others.