Yes, I have.
One was relatively short lived, it was a celebrity and not one I had any hope of meeting so there were obviously limitations as to what I could do (ie nothing). But for about two months I was completely infatuated to the point I didn’t get any work done as spent hours googling and reading about him. I also bought dvds of his early films that had to be shipped from the US.
I had a job interview during this time and I even managed to shoehorn him into that conversation which is something that comes back to haunt me to this day
(Needless to say, I didn’t get the job, but surprisingly that wasn’t the reason, and I did actually get a job at that firm at a later date).
In hindsight, this was in the run up to my wedding and I think I was having cold feet / second thoughts and it just came out in a strange way.
Another one was an obsession with a man from
a hobby. We flirted and that’s as far as it went externally but internally I was obsessed and thought about him 24-7. I would do my make up and put on fancy underwear when I went out to the hobby, just “on the off chance” something happened. In reality, I would never have done anything, and it was just never even really a possibility. So the fact I did this is baffling to me. This was a year or two after I got married and I’m not sure what caused it. I’ve never cheated and pretty sure I never would.
The other notable one was many years ago when I heard that an ex boyfriend had died. We had quite a short, volatile relationship and I didn’t think of him much in the intervening years. Until he died and I suddenly started mourning the life I could have had (he had quite a glamorous job and had a very comfortable lifestyle living in Europe (various houses) and I became obsessed with the fact that I could have been living that life. I contacted his widow to pass on my condolences and she replied and was very polite. I didn’t say anything inappropriate, just said we had known each other years ago and the exchange was fine, but internally I also became a bit obsessed with her and looked all over her socials etc. Very much regret being such a creep and even messaging her at all. Luckily I did keep all that creepiness hidden, but I still regret it.
I’ve had other crushes over the years, but those are the 3 that stand out as having gone too far.
edited to add - I do have a personality that get hyper fixated on things