An important feature of intentionally kind acts is that they help another person, or at least another living thing, move toward accomplishing something that helps them thrive. By that definition watering your yard helps the grass grow, and therefore is a kind action directed to those many individual grass plants.
But there are usually unintended plants living amongst the grass, plants that we may think of as weeds, and while we are watering the grass we are also watering those weeds. This isn’t an intentional act of helping the weeds to thrive, even though watering the yard is an intentional act. It is an unintended consequence of an intentional act that the weeds thrive.
Some weeds are beautiful, such as dandelions, but they are usually thought of as out of place in a smooth grassy yard. If there are only a few weeds they can be dealt with using hand tools, but if there are a great many weeds a specific weed killer is the better option, or we can intentionally choose to ignore the situation. Of course, ignoring the situation is distressing the grass and that is what we intend to help thrive.
In the example, I have replaced human interactions with plant interactions, but from the point of view of cultivating kind habits it is a good practice to begin with something easy, so we are more likely to attain success. It is instantly difficult to begin interacting with other humans because we must pay attention to their words and actions, and we are easily distracted by everything they say or do.
To help another person it is necessary that we know what they need. That is very complicated, but there is a universal human need and that is for another person to pay attention to them. With that in mind when you enter a conversation you can probably intentionally create kindness. The reward for that specific type of kindness is that you develop the habit of paying attention to satisfying your own human needs.
Giving an intentional kindness may not help another to thrive, but it will help you thrive.