When it's a match
Having recently joined a company that matches millions of people every day with their possible new partners, it struck me that starting a new job is quite a bit like dating.
At first you are eager to see all the surface-level positives after those first early dates: you tell all your friends (or anybody who bothers to listen) - great perks, yes lovely people!, wonderful commute. Motivated to post-rationalise this quite large decision you have just made (the post-hoc fallacy is only human), weather it was to change jobs, or partners, you show your new asset off to the world to see. In the early months you tell everybody how great everything is and how yeah, it's a bit of a whirlwind to you both.
As the months pass you get to learn about your new partner - you'll have your first fallouts at work, you tire of conjuring a giant smile to every passer-by in the office corridors, you're no longer bothered to wear your smartest attire to work, gradually swapping it out for your office-pajama regular. Things settle down. You crack on with work, and alike to that first fart in presence of your new beau - you get comfortable with each other.
Like in a relationship that soon just feels right and is not stuck waiting for that 'are-we-in-a-relationship' conversation, your probation period whizzes past without anybody noticing, because you are both too busy getting stuff done, enjoying each other's company.
You go quiet, comfortable in that what there is between you two is somethings special. You no longer feel the need to over-enthusiastically list the benefits of your new partner at dinner parties. You'd better keep it to yourself - because you know you've got yourself a keeper.