Key confusion

Chris and I went to drop off my car for its yearly inspection tonight. He drove my car and I followed in the 'Blue Angel' so we could get back home. Before we left LJ had warned me that the van may not start again, don't turn it off, and call if we need her to pick us up. I was expecting something to go wrong! So anyway.. after I had dropped off my key in the overnight slot, we hopped back in the hardly-running beloved old van and I could not start it! I'm not talking about the engine not turning over or spark plugs or what not, I just couldn't turn the key in the ignition. Chris pulled out the owner's manual and was reading what to do, he tried turning it himself and it wouldn't budge (so no, it was not my weak arms that was the problem!). Eventually he got over in the driver's seat to give it a shot, and after about 5 minutes of struggling, pulled the keys out of the ignition and asked me if I was sure I was using the right key. Well.. turns out I put the wrong key in, and of course the key to the taurus wouldn't start the van.. Oh did I feel foolish!