It's been ages since I started using it, but I don't think it was any problem in particular. I think I just happened to watch a video by Scott Wlaschin one day and was intrigued by the weird language and the things he was doing with the type system, having only been familiar with object oriented programming at that point in my life. I kept coming back to it and eventually it became my bread and butter.

What I like most about it is the type system (discriminated unions, etc.). It's really powerful and intuitive, without letting me go overboard "big braining" the perfect type for every situation like I tend to do with e.g. typescript or haskell. F# is also great because we can access the full dotnet runtime and nuget ecosystem. I have several projects where I mix C# and F#, and they're perfectly compatible.