Why is St. Patrick's day celebrated by drinking?

Is anyone else confused how St. Patrick's feast day turned into an excuse for everyone (Irish or not) to go get drunk? It's ridiculous in my opinion and I don't like it. Does anyone know how this tradition began? I can understand celebrating St. Patrick, he was a great saint and definitely deserves celebration, but I can't imagine he's thrilled that everyone celebrates this day by drinking all day and all night. I drove Paulina to the library at around 2:15 and it took 45 minutes to get there and back, that's more than twice as long as it would normally take! Traffic from all the drinkers. Sigh. Grossest thing ever, we were stopped at a light and the guy in front of us opens his door and pukes. It was absolutely disgusting. Eck. People are so strange, I don't see the attraction in drinking, making a fool of yourself, puking, passing out and waking up with a hangover not knowing what exactly you did in your drunkeness but feeling vaguely uneasy. So that's my opinion of St. Patrick's day drinking. A few drinks is fine, but please for your sake and everyone else's, don't overdo it and don't drive afterwards!!