A guardrail in driving is "a system designed to keep vehicles from straying into dangerous or off limit areas". We don't usually argue that guardrails shouldn't be present on bridges, medians, or cliffs. In driving, we acknowledge that there are some dangers beyond the guardrail.
In our lives, we also acknowledge danger somewhere out there. But we usually do not acknowledge that we need guardrails to protect & direct us away from that danger.
Our culture will not encourage us to establish guardrails, in fact they most likely will not understand them at all. In Ephesians 5, Paul says that we must be careful how we live, as wise not unwise, and taking advantage of every opportunity.
What area of your life do you need some guardrails?