I bot TQQQ @55.21, got filled, waited for 1 hour, put a sell@56.21 order.
10 minutes befire closing bell, TQQQ is around 55.0, I thought the order won't be taken. However, after 4:00pm, I saw TQQQ is around 56.4!!! from yahoo (it gets 15 minutes delay). I went back to my account, shit! it got executed. I wish I had this luck every day.