Because most buildings now they just put one button so people stop clicking both

That has not been my experience, and logically it doesn't really make much sense. If you do so, you are making the problem strictly worse.

what 3 hours ago | parent | prev [-]

What? I’ve never seen that. The elevator needs to know which way you want to go.

	▲	allannienhuis 21 minutes ago \| parent [-]
		On the ground/lowest floor, there's only one button as there's only one way to go.