This is the 8939th most frequent Japanese word.
気持ちいい
"Feels good" or "pleasant."
The word 気持ちいい is used to describe the pleasant sensation of the massage, focusing on physical comfort.
このマッサージはとても気持ちいいです。
This massage feels very good.
The word 気持ちいい is employed to express the general pleasantness of a situation, in this case, the weather.
今日の天気は気持ちいいですね。
Today's weather feels nice, doesn't it?
Here, 気持ちいい highlights the enjoyable relief and refreshment experienced after a specific action.