For the longest time my mind said alcohol = fun, I lived this way until my mid 40s and my liver made me stop.
Anything I was doing that was already fun was instantly more fun by adding a drink!
Gotta work all night? Who cares I'll just do a couple shots! Tending bar in at a hot spot makes it all the easier.
When I first sobered up boredom was huge, I went to instantly hating my job. My wife and I own/run a wine bar, hanging out at work and watching over things was just hanging out at the bar and having a couple. Bars have been a huge part of my life, I dreamed of owning one for a really long time before it happened.
I get the wistful thinking thing but I've learned now that alcohol =! fun but it took my brain realizing that what I thought was fun for the last 25 years was not the only way to have fun. There's a whole world out there.
These days I think of it more like an old friend that screwed you over so bad that person has been removed from your life. Yeah, there was some fun but in the end that person was bad and used you.