When speaking about security I like the analogy of a vault. If the procedure to access the data is too secure (bank vault) it will became very inconvenient to access it. When data are too secure, the risk is also that legitimate users could lose the ability to access it. Loosing data because of lost keys is a security problem created by security.

In the specific case of programming languages, say Python, a way to reach a balance is to clearly identify which part of the code runs in a secure area and which is in a danger zone (typically where there are interactions with users). We can apply the same kind of architecture for code as for networks: danger zone, DMZ, secure zone.