Exists is the enemy of good
We've all heard the adage "perfect is the enemy of good." I take this to mean: if you only accept perfect, you might miss a good-enough solution. I still try to strive for perfect, but have learned to accept that good might be sometimes enough.
However, I've been saying something to friends and colleagues—for probably a decade now—that is closely related: exists is the enemy of good.
This idea is pretty simple, in principle: sometimes we miss a good-enough solution because a not-quite-good-enough solution is already out there and in use.
When I came up with this, it was specifically about bad software that seems good enough. Usually, stakeholders are less willing to invest in a good solution when one already exists.
Who of us hasn't hacked together a prototype that somehow became the code we released to production and has been doing a not-quite-good-enough job of serving clients since that fateful deadline? In my experience, these things often become absolute nightmares when it comes to maintenance (and security, and performance, and stability…), but they exist, so the urgency to replace them with a good version gets traded for the thousand papercuts of unexpected "well, I didn't think this would happen, so it's going to take me a few more hours than expected" or "oops; we didn't expect this kind of vulnerability…"
Or, we've cut corners: "Yeah, we've been meaning to fix that wildcarded security policy, but it's working for now, so we haven't made time to tighten things down." It exists though, so making it actually good doesn't get priority; it gets kicked down the road—sometimes forever.
