Yes, the "optimum quality before" date is radically different from the "safe for human consumption" date.

For grains/flours, it depends on whether natural oils/fats have been left in place or processed out. Oils and fats go rancid over time. So, whole wheat/grain flour will go sideways long before white flour. Temperature and oxygen exposure are big factors in this. Trust your nose -- if it smells off, it's compost material unless you keep a pig.

For canned goods, food banks have a carefully established metric that applies regarding the "safe for human consumption" date, which is legally defensible and eminently practical. Waste is the enemy IMO.