The first verbs you learn in most languages are in present tense: I walk, you eat, we read, …. To live in the present tense is reassuring and concrete: there are no regrets, no memories, no fear of what has not yet happened. It is very liberating: taking the moment as it is, aware of it as it happens: Pain or pleasure.
It is like when I swim: just me and water, floating weightless, aware of body and its motion, strokes cutting into water, the muffled sound under water, a total immersion, a moment of release and purity. I don’t like it when I swim with my mind on 1000 things I need to do, like to do or should have done. Then the swim is over and I have lost the time without gaining the pleasure!