It is neither laziness nor convenience issue. Some of the small groceries are like that. They do not have any pricing policy. They are over charging many people on many items as they dont have enough cusotmers now and they are taking the advantage of such customers who are in a hurry. Their rents would have gone up and they dont have enough turnover to cover it on a daily basis and they are squeezing everyone who is shopping there. Most of their customers residing nearby are not hypermarket custormers and are unaware of the market prices of tomato or marrow so they pay what ever the grocer ask them to pay and eventually they will charge every one in the same manner.