I need a word for this emotion and I can't think of one. Thoughts?
Some vocabulary options include:
Schadenfreude (as suggested by @DWKraus) - pleasure and enjoyment that is derived by someone from another person's misfortune, i.e. "leopards ate my face" scenarios of karmic retribution.
"Guilty pleasure" - something that is secretly enjoyable but which you feel bad for enjoying, i.e. eating lots of unhealthy food or binging a terrible TV show.
Vice - similar to the concept of a "guilty pleasure," something that is self-destructive, negative or bad for you that you shouldn't enjoy and feel bad for enjoying, but you do anyway. The usual examples are smoking and drugs.
Indulgence - something extravagant or overly luxurious and unnecessary that you enjoy, but also something that is generally selfish and that society in general might frown upon. When you "indulge" someone in something, it often carries the implication that you're letting them do something selfish or self-seeking.
You may be thinking of despite oneself, defined by the venerable Merriam-Webster as:
even though one does not want to
Relevant example from this source: "Despite myself, I began to enjoy the movie."
Another is weakness,. Combining the senses of “a special desire or fondness,” a lack of strength, and a personal failing, you get an improper desire for something that one is weak for giving into.
Some more words that could be helpful include: self-, irony, irreverence, whimsiness, raunchiness/crassness, archness ("inappropriate playfulness"), superficiality, impropriety, iniquity, dismay, chagrin, displeasure, distaste, disquiet, disbelief, cognitive dissonance, imprudence, bipolarity, perversity, internal conflict, turmoil, dissidence, dissatisfaction, displeasure, discomfort, incongruity, ruefulness, regret. indignity, disgrace. I found these primarily by recursively looking through results from OneLook thesaurus / reverse dictionary and WordHippo thesaurus.
The word that might fit your question best is ambivalence:
The simultaneous existence within a person of both positive and negative feelings toward another person or action, or toward an object (as of attraction and revulsion), resulting in internal conflict.
Perhaps my answer will at first surprise you...
verb (used with object), sur·prised, sur·pris·ing.
1 to strike or occur to with a sudden feeling of wonder or astonishment, as through unexpectedness:
// Her beauty surprised me.
2 to come upon or discover suddenly and unexpectedly:
// We surprised the children raiding the cookie jar.
3 to make an unexpected assault on (an unprepared army, fort, person, etc.). 4 to elicit or bring out suddenly and without warning: 5 to surprise the facts from the witness. 6 to lead or bring unawares, as into doing something not intended: 7 to surprise a witness into telling the truth.
1 an act or instance of surprising or being surprised. 2 something that surprises someone; a completely unexpected occurrence, appearance, or statement:
// His announcement was a surprise to all.
3 an assault, as on an army or a fort, made without warning. 4 a coming upon unexpectedly; detecting in the act; taking unawares.
But is it not the perfect single word for this requested emotion? — one so common and mundane, & yet nonetheless so complex, surprisingly so...but then again we are intelligent to an extent that is endlessly surprising us, as we learn more and more about the true scientific nature of not just ourselves, but all of life. It's a nightmare, and Heaven all at once. Don't take it too seriously, but you can't really help it, can you? 𝐞𝐭𝐜. In the end laughter is a necessity for simply getting through it, in despite of all its horrors, we love it. And why!? I suppose otherwise we wouldn't be here, after all. Not after how long we have been!
This is technically joy at the suffering of others, but it can be applied more broadly to satisfaction at things that are perhaps inappropriate, like being a little happy when an actively anti-mask and anti-vax person gets COVID. It can apply to guilt, but if you are happy about something unhealthy (like sadism, child abuse, taking drugs) then that's a different class. At that point, it would be more shame or guilty pleasure.