$SPX - Chart Link - Thursday shows a good example of a breakaway gap. Many people are scared to chase and buy gap ups, but these breakaway gaps are ones that you chase, you buy them! 

They occur when price gaps strongly over a resistance trendline. These are not gaps to be scared of. Yes would have been best to be long on that Wednesday close, but on Thusday's cash breakaway gap, that was also an opportunity - for a trade anyway