I shared a job announcement with a colleague who I thought would be a great fit for the job. She isn’t looking for a new position so the possibility of leaving caused some soul-searching and stress.
My advice: send in an application. Applying for a position is radically different than accepting a new job. You may not get an interview (or even hear back), but if you do, the process often clarifies things one way or the other. Even if you interview, you may not get an offer but if you do, the terms may also make your decision easier. There is little to lose by applying.
Oh, and those great people you work with now that you would hate to leave — I have learned throughout my career that there are great people at many jobs. You’ll have a better sense of that in the interview process as well. You can remain colleagues — and even friends — with the co-workers and bosses you leave behind, building your network as well as your skills in the new role.
Don’t count yourself out too early in the process. Take that first step and see what happens. Save the angst until you’re actually deciding on a firm offer.