The problem is that we sometimes have to take risks knowing that our decisions may backfire on us.
I shouldn't have said it that way because this phrasing begs the question. We don't "have" to take risks in many cases. We choose whether to do so or not. We could simply choose to live in our caves on bread and water and forgo the possibility of many activities that may bring significant pleasure but at the cost of significant pain. If "all pain is to be avoided at all cost" is the formula, then the cave-dwelling life would be a logical option. But that doesn't appear to me to be the formula Epicurus taught, nor does it make sense to me that he would have taught it.