I joined a startup a decade ago which was great and taught me a lot in the early years. I stayed all that time though because of options. Made a bit from them, took some time off for personal study/projects, and eventually moved to a bigger company to start learning something outside the small technological bubble I'd been working in until then. I don't know if I made wrong decisions but I feel a bit bad about it because I love having highly skilled colleagues, learning new technology and how things are done by teams that do them well, and I think I could have got to a significantly more technically advanced position than I am now by not staying so long at the first place.