The greatest skill you can acquire is to learn to have a really good time by yourself.
And that does not mean binge watching Netflix, or scrolling on social media. That is you trying to escape yourself and your life. But spending time doing things where you are actively involved like cooking, playing music, reading, learning a new skill etc.
People who can do that well also make for great friends, colleagues, neighbours. Their cup is always full so they come out into the world with good energy. They are not seeking someone to make them feel better, instead they are the person who makes everyone else feel good.