There are two types of smart contracts. One. The owner administrator can change the tax. That is, people pay a commission when buying and selling. Imagine. (Sometimes this tax is 10% on purchases and 10% on sales (this does not work inside centralized exchanges). The second type of smart contracts. These are smart contracts that do not have the function of trade tax and transaction tax. And there will always be different amateurs easy money. They will put their bots. On the dex exchange. On contracts where there is no tax. These bots will see you and make transactions and buy or sell faster than you.) Therefore. In settings. Before the deal. On the exchange dex. Don't make it big. Price slippage. Otherwise, your transaction will be completed at an unfavorable price for you.