I'm so good at this investing stuff! ... Well, maybe not so much

I've made it a habit, here at New Company, to regularly log into the Benefits Page on the company intranet to see how my investment accounts are doing, since they make it so easy here to do so. My rollover IRA from Old Company is with a free advisory service here at New Company and it's interesting to watch how they invest this money. With my regular New Company 401K account however, I've chosen the funds for my investment myself (basically through the "throw a dart" method). Since I am generally an idiot about such things, I like to keep an eye on it -- not that I would really know what to do if I saw something alarming, but still. Anyway, this morning I logged in and got really excited to see that this account has grown by about $2,000 over night! WOW! I thought, 'I must be doing something right here!' It took me a few minutes to remember that payday is tomorrow and this increase just represents the contribution from this next paycheck. Duh, maybe I'm just an idiot.