Not fun at all because at some point you'll need to stop and when the time comes the withdrawals can be quite severe. And even if you manage to quit, what are you going to do with all the pain, new emotions, sadness, depression. The time you've loss.
Fentanyl is a very strong drug but super heavy not fun at all. You may feel a good analgesia if you are on pain but there's no euphoria at all. Oxies have a very quick long lasting period and normally you'll need more and more to feel the same. Same for dilaudid. Opiates are not fun, they make us live like that guy on 'click'. No big emotions, isolation, at some point or another you'll have serious money problems and it's more and more obvious that you turn into an unhappy person after sometime.
You can live your life and achieve your goals and do opiates at the same time. It's already very hard to have a girlfriend or maintain a marriage. You become a zombie and nobody wants that. I get that it makes us feel good and cosy. It makes all problems fade away but that sort of life but we end up paying a high cost for that. Emotionally, physically, socially and psychologically. I have been addicted to opiates for so many years and I'm now sober after trying to quit so many times, at least once every 6 or 8 months. It's not all okay when you decide to be sober as you need to rebuild all of your life and realize that you missed so many things.
I'm not judging your choices, I have done mine. I'm just trying to share some of shit we have to go through and most of it is impossible to erase. If only people could go back in time to make a different choice..