The traders employ quants who are paid huge amounts to obsess over trading patterns for much of the time they're awake. They program computers to automatically read the news faster than you. Long-term investor? Good luck finding a good time to sell.
It's a warzone and the computers aren't just fighting to get that marginally good deal first, they create unnecessary trading patterns to fool each other. If a market goes haywire, the controllers will sit there, wondering if it's just a ruse by a competitor.
And just remember your pensions are involved in this.