I've driven in places where a few seconds was just how long people sat at the green light. I didn't get it until I was there long enough to notice how insanely often cross traffic was definitely successfully sneaking through that yellow at the last moment.

I don't do it to that extent, but I do now give it a few beats to account for other drivers insanity.

I try to assume positive things, so if someone hasn't gone after a few I tend to assume that they've done what I know I've done, which is to pull up to the light and rather than intently watch the light, to keep looking at the road and cross traffic and just not notice the light change in my upper periphery.
Way more common if there's a protected turn at the intersection or it's otherwise not symmetrical.