If you grow your own tomatoes you can use cultivars that are optimized for taste, not for looking beautiful on a shelf for several days after being transported a hundred miles. It also helps to pluck them only when they're most ripe.
Home grown tomatoes taste more flavourful because they're allowed to ripen on the plant. Many store bought tomatoes are indoor when picked then ripened with ethylene gas.
Growing up in Northern Europe I spent the first ~19-20 years of life believing I didn't like tomatoes. Then one day when I was in Italy I had a tomato bought from a local farmers stall in some small village and realized that I tomatoes can be awesome.
Still don't like most tomatoes available at supermarkets though.
You may be trying tomatoes from the same region. Comparing North American tomatoes (personal experiences include Ontario and N/S California) versus European (Italy/Swiss), the taste, sweetness and juicyness, is more bland in North America.
As for tomatoes from the same region, I've never really tasted a difference either.
