I always think of us as having two eyes, two ears for stereo vision and sound but never think of us as having 'two noses' to determine the direction of a small or two different smells at the same time.
Doing that in supermarkets here is also looked upon as a bit weird. But I don't care, I prefer to look weird and eat the best tomatoes ;)
They won't beat summer sun grown tomatoes in warmer climates, but they're available all year round.
A bit of sugar and a bit of acidity can boost the flavor of sub-par tomatoes, for example for a sauce.
- smell them. Smell is part of flavor and also correlates with the other parts of flavor. Odorless tomatoes are 90% of the time tasteless
- choose tomatoes which are still attached to a part of the plant when possible. They keep their flavor a bit longer.