Perhaps "conviction in your trading plan and your ability to follow it." I have a friend, quite well-off, very smart, Ph.D. chemical engineer who was laid off from his $350K/year job. At his age, it proved not easy finding another comparable position. He decided he would day trade while waiting for an offer. I showed him a very easy, very mechanical set up. He demo traded it for two weeks, thought it was the greatest thing since sliced bread.
The first day he goes live the market closes and I don't hear from him. I was surprised, because I had a chart template set up for that system that day knowing he'd be trading it and he should have had a very nice day with four trades, three +4's and one -2.
Finally, I texted him, "hey, how did it go today."
His response: "Terrible

A $100 loser and three breakevens ... your system sucks only works in demo account"
He never did find another engineering job close enough to home and they didn't want to move before their kids graduated from high school. So, you care to take a guess at where he's working ... I kid you not ... Home Depot.