Most commuter bags fail in the same small ways. Here are the six details that separate a bag you tolerate from one you stop noticing.
One, the back panel
It should be flat and slightly firm. Bags that bulge into your spine do it because there is nothing structuring the panel, and no amount of strap adjustment fixes it.
Two, strap geometry
Straps should leave the bag angled slightly outward, tracing your shoulders instead of cutting across them. Parallel straps on a wide bag will chafe at the neck within a mile.
Three, the opening
You should be able to see the bottom of the main compartment without turning the bag upside down. A wide horseshoe zip beats a narrow top opening every time.
Four, the laptop sleeve floor
It must stop short of the bag base. A sleeve that runs to the bottom puts your laptop edge on the pavement every time you set the bag down.
Five, the outer pocket you actually use
One quick-access pocket, sized for a phone and a card, reachable without removing the bag. More than one and you will forget which is which.
Six, how it stands
A bag that falls over when you set it down will annoy you daily for years. A flat base with a little structure is a small thing that pays back constantly.