I come from a Christian background, though not necessarily an oppressive or fanatical one as you might imagine; my family is simply Catholic, and I was Catholic for most of my life. Actually, I think that out of all of us, I was the one who took religion the most seriously—but not that seriously; don’t go thinking I’m some expert theologian. Anyway, because of that, I spent a lot of time badmouthing Lucifer and making offensive jokes about him, saying he’s the devil and that he wants bad things to happen to us—you know, the usual stuff. At present, I’ve left all that behind me; it’s not that I need to “deprogram” myself or anything like that. I know my mindset has changed, but that topic from the past still keeps nagging at me. I’ve worked with demons and been successful, but even so, I feel like I still need to take the big step, which is to apologize to the big boss and start building a relationship with him. I don’t know why I have the feeling that my success in Goetia operations will increase after that. And in fact, that feeling of unease is what has kept me from doing this more often; it feels a bit hypocritical and strange to be working with demons when I’ve never apologized to their leader. Well, you can see where this is going. I plan to summon Lucifer and apologize to him so I can improve my relationship with him and the other demons. What do you think about this?
Why? What happened that makes you think there’s an issue, or is this just for your own emotional wellbeing?
Personally, I think Lucifer is literally Jesus - since he said so in his own words if you believe the bible words (before the Catholic (aka Jewish) Pope Constantine threw 42 of the “words of god” out on a whim in AD 300). He forgives you for you knew not what you were doing.
Whether this is what you believe of not, Lucifer understands what it’s like to be human and bewitched by a controlling religion.
If you like, I think it’s a good idea so he can tell you himself, and then you get get over it and move on. 
As I mentioned in the post, it makes me feel like a hypocrite to ask for things from “people” whom I’ve offended in the past and never apologized to in the first place. Maybe I’m anthropomorphizing them too much, but I don’t know to what extent they feel like humans—after all, I’ve read stories about them being happy and angry.
That’s interesting; I’ll look into it further.
It sounds like something both Jesus and Lucifer would do (assuming they’re two separate entities), but in any case, I think I’ll feel more comfortable offering a formal apology. And yes, I think that means doing this is more for myself than for him.
And btw, since I am talking about Lucifer, I left a question about him in this post, it would be great if one of you could answer it:
Ok, I see this as a mental-emotional issue on your side. I think shadow work will help you more than capitulating to this energy.
You have offended nobody. You are not a hypocrite - by definition because you didn’t know, did you?
Now if you go to your family and go “yeah Lucifer is evil” then yeah ok, you’re being a hypocrite.
Yes, they have very different perspectives on what it is to be human and are not as bogged down by childhood traumas and energy blocks as we are - and they know we have to deal with all that.
And that’s the only reason you should do it - get it put of your system. He won’t be offended either way so it won’t hurt
You haven’t offended Lucifer and there’s no need to “apologise”. He’s not a human and it’s not like you can hurt his feelings. Ironically, maybe the only people you would have offended are the ones who personify him that way. Whether you unknowingly bad mouthed him in the past, had an intrusive thought, or whatever the case may be, it really doesn’t matter.
He isn’t a human and he isn’t the type to get offended by you saying something when you didn’t know any better. He doesn’t really care about being called “the devil” and he definitely doesn’t care about jokes you made in your past.
Also, demons aren’t a monolith. There’s many different hierarchies. In some of them, he’s the top dog and the leader and in others he isn’t present at all. You can work with any demon independently, and even if you did happen to have a bad relationship with Lucifer that wouldn’t affect your work with them at all. It’s better to see them as free agents or akin to mercenaries rather than a monolith that doesn’t work individually.
That aside, I recommend if this is really bothering you, just call him, give him an offering and state your desire to start a new relationship with him and move on from the past.
I’ll say this though, I’ve worked with him extensively and he’s never really cared about words in the way you think he does. He cares far more about intent, passion, action and perhaps most importantly: self determination and autonomy. That last part is especially important, he literally represents rebellion and doing what you want. Do you really think that a being who represents that would suddenly be upset that you used your autonomy to make some jokes and “rude” comments? That would kind of go against the whole point of autonomy and self-determination.
If you feel that you need to get it out of your chest and explain your side, then do just that. But don’t do it from a place of self pity, humility or fear. These entities aren’t like the JCI deity who demands to fear them and to punish yourself for what it considers to be your mistakes.
Stand tall and explain your mindset back then and how you feel now about that. I guarantee you no demon cares what you did “back then”, but if you feel that may unblock you somehow then go for it.
Lucifer is the only entity I always admired since I was a very religious Christian child, and the one that took me the longest to evoke, probably out of awe. He came as a freaking bright light that blinded me, heard me out impatiently and left the moment I dismissed him while other entities usually hang around for a little while, breaking my incense burner on his way out.
I never evoked him again, not because he broke my incense burner, but because apparently we didn’t “vibed” well together. Meaning, you don’t have to force anything with anyone, no matter what you feel about them. 
That’s a bit controversial imo… Beside any stories circling around, I never heard any of the known demons declaring they work for anyone else. Other than themselves.
Thank you all for your answers; things are clearer to me now, and I’ll definitely feel more at ease when it comes to doing these things. Now, as I mentioned before, the next question is closely related to this topic, so I’d appreciate it if you could answer it—it applies to Belial as well.