What's the reason behind the wild green wig?

For the longest time today I was completely oblivious that it was St. Patrick's Day. We had planned to go to Mineral Wells state park today. Last night we took the van into the shop to see if they could take care of the problem that was making the check engine light come on. We got the van back this morning only to have them tell us that our two front tires were showing the threads which was not good. This was confusing because we got all new tires last June and they should have been good for 40,000 to 60,000 miles and they had gone bad after only 4,000. Where did we get the tires from? Walmart. Would they help us out and take care of the problem? Being Walmart, of course not. By this time it is around 11:30 in the morning, an hour and a half past the time we had planned to leave for the state park. We went over to Discount Tires which treated us well in purchasing new tires but they don't do alignments which is what was needed to prevent the thread problem on the tires. As we were standing in line at Discount Tires, one of the mechanics walked from the garage into the lobby and he was wearing this wild green wig. I looked at him and my first thought was, " What in the world was the reason behind him making that choice?" It wasn't until an hour later when we went back to pick up the van that I saw a customer come out of the building wearing a funny green braid in her dark brown hair. It then dawned on me what day it was and the reason behind the wild green wig became clear. I also realized that I wasn't wearing a single stitch of green and since I wasn't in the best of moods after having our plans for the day go flying out the window it was a good thing that nobody tried to pinch me.