"Afterthought of affluence" refers to something that is considered only after wealth has been acquired, usually a luxury item or indulgence. There are several synonyms for this phrase, including "posterior reflection of wealth," "retrospective luxury," and "belated extravagance." These phrases all convey the idea that the object or experience in question was not initially a priority, but has been indulged in after wealth and financial security have been attained. It's important to note that while these indulgences may bring temporary enjoyment, they do not necessarily lead to true happiness or fulfillment.