1.) No pivot data. I came in late, and so wasn't thoroughly set up.
2.) I didn't wait until the opening trend failed/reversed (or not) to take the trade counter to my first, successful trade.
3.) Right at the moment I should have sold, I made a phone call to my dad, again, because I was late. I usually call him before the market opens.
4.) I didn't sell the moment the trade went against me. All "oops" moments must be sold in the future.
5.) I didn't see yesterday's close, and so did not read it for the short-covering rally it was.
6.) I noticed that the EUR/USD - SPX trade had decoupled in the last 24 hours, and ignored it.
7.) I have a slow hardware/trading interface issue. The thing freezes up, and minutes pass, before I know what has happened. This should keep me out of the market, until I get a new computer!
8.) Known data delivery issues at the NYSE. This will make everyone freak out, and sell, even if they wouldn't have. Since the data is delayed, these sells will hit much later than they would have, and will cause a waterfall effect, when they catch up to real time.
9.) Am I leaving anything out? Oh, yeah ... when I saw people selling their longs on Twitter, people who do this for a living, and who know what they're doing, I did not sell. Doh!
"Get those brokers back in here! Turn those machines back on! Turn those machines back on!"