I think of the Four of Cups as the bored housewife. A time of solitude, enui and discontent.
You have a lot, materially and emotionally, but have grown bored with the status quo. Days go by in the same old routine, with nothing to break the monotony.
As the boy sits, sulking, and feeling sorry for himself, he doesn’t see, or ignores, what is being offered to him by the mermaid. This could be an offer of friendship, or an opportunity to expand your horizons. It’s time to snap out of your funk and find what is missing in your life. It is likely right in front of you, you are just refusing to see it.
Only you can improve you life, if you are unhappy, then do something about it. Self pity and blaming others will get you nowhere. Open yourself to new opportunities and experiences. The smallest of changes can often have big results.