What skill did you develop after 25 that had the biggest impact on your career?

For me it was learning to communicate clearly. I was technically good at my job for years but I couldn't explain what I was doing to anyone who wasn't technical. My manager literally told me the only thing between me and a promotion was how I presented in meetings.

Started actively working on it at 27. Did daily speaking drills, recorded myself on calls and listened back, studied how good communicators structure their thoughts. Within about 6 months I got more visibility and opportunities than the previous 5 years combined. Nobody tells you that communication is the bottleneck, you have to figure it out yourself.

I've been compiling speaking exercises and frameworks from communication courses, Toastmasters techniques, Stanford speaking research and posting two a day in r/SpeakBetter. If anyone else realized this late that speaking well is the meta-skill for career growth theres a lot of useful stuff in there.

Curious what other skills people here developed "late" that ended up mattering more than they expected.