Quote from overspool:
When I first started trading options (like my 3rd or 4th option trade) I bought some calls on AMAT right before market close the day before earnings. Bought them at about $.45 per contract. Earnings were fine but they lowered guidance so the stock took a nose dive in the after hours and pre-session. Being an ingorant rookie I put a market order to sell in for right when the market opened hoping I could catch it on the way down. It opened at $.05 and I lost it all.
The stock rallied througout the day and the calls closed at $1.25. Learned A LOT.