Too many customers obviously won't increase your profit, and if you're selling things at a loss to them, I don't think that's a good way to attract more customers. Instead, treat your customers well and stock your store with a variety of goods so they can make the perfect choice when they visit. As you mentioned, treating your customers like kings is another great way to boost your revenue because they'll notice when things are going well in your store.
Having many customers and making a small profit from each sale might be better than having few customers and making a huge profit from them. An example is having 10 customers that you make $10 from each of them and having 100 customers that you make $2 from each of them. The former will bring $100 and the latter $200. Attracting more customers is an important factor in business growth and profitability.
I agree, we don't need to make too much profit for each product sold, but instead can make a small profit but attract many customers, the total profit will be huge. If we sell cheaper than our competitors, we can retain old customers and attract new ones, which is a huge advantage that many large enterprises are applying. We are consumers ourselves, and we know what we need when we go shopping. Therefore, when doing business, always put yourself in the position of the customer, then you will gain the love of customers.