I am assuming you are honestly looking for reasons, so here are a few that come to my mind:
Maybe you can consider that even though THIS health check up was good, it's increasingly unlikely as the years pass that they will continue to be good if you drink too much.
Your photo looks on the young side. It's pretty easy to roll with the punches when you are young, but you are putting a burden on your body and at SOME point health issues will arise. You are asking your liver to concentrate on alcohol all the time rather than do it's regular job. And, you are dehydrating yourself regularly, and substituting empty alcohol calories for nutrition. Logically, this will take a toll over time.
Also, you look very pretty in your photo. One great way to age yourself quickly and lose good looks is to over-drink. Anyway you slice or dice it, that is undeniable. That is a pretty good motivator too! Vanity is a silly reason to get sober, but hey, everyone likes to be attractive.
For proof, look at the paparazzi shots of those celebrities overdoing it in the drink and drug world. Usually not looking their best. Look at poor Whitney! She was so beautiful as a young lady, and looking pretty rough towards the end.
And... black out stage would be scary for me. Wonder if something happened in that state that you are accountable for, like you choose to drink and drive and hurt someone, etc?
Hope these ideas help to motivate you!