The recently updated Gmail web interface has been polarizing. Either you love it or hate it. But something almost everyone can agree on is how horrible the contacts manager is. It's difficult to find (tucked away in a drop down under the Gmail logo); you have to manually merge contacts like it's 1997; heck, sometimes your contacts will simply disappear. While there have been some improvements in recent years, most are really just band-aid solutions that mask a fundamentally bad approach to storing and managing contacts.
More Contacts is tangled web of unnamed contacts. 
Take, for instance, the way contacts are added to the manager. You can create contacts manually. But Google also automatically adds contacts to your list when you reply, reply all, or forward to an email. It sounds like a good idea unless you already happen to have that contact in your list and the Gmail information is slightly different (outdated perhaps). Now you have multiple entries for the same contact. And if the person you reply to doesn't append their name to an account, you sometimes end up with a list of random email addresses without names.
On top of that, the "Most Contacted" section of the manager isn't based on time but the amount of emails in a thread. Even if you haven't talked to someone in months, they'll still show up there. That's means you'll see everyone from old Craigslist buyers to former work colleagues – not all that useful. And because Google still wants everyone to use Google+, it pushes adding a person to Google+ over adding them to your contact list inside an email.
Overall, it shows a surprising misunderstanding of how people actually use email and what's actually useful. And now the mystery behind this persistent mess seems to have finally been solved.
Replying to a tweet from Redpoint Ventures partner Ryan Sarver, former Google design lead Kevin Fox shed some light on why using contacts in Gmail is such a pain.
So I guess it all came down to a to-do list, priorities, and timing.
