I saw one once. Deceptive. Their webs are large and irregular. Worst of all, the initial bite doesn't hurt that much but then the bite blisters and creates a nasty ulcer.
I find a couple of black window nests in our garage every three weeks or so in the summer. I feel bad but I kill them. They nest in walkways and corners where people might brush against their nests. I don't want the family getting bitten.
I tore the large garage door frame apart once when I found one hiding behind the frame. Not good if the little guy fell onto someone as the door opened.
The tell tale sign of a black-widow — lots of dead hard-shelled insects near their webs. They are one of the few spiders that have large and strong enough fangs to penetrate the shells of the insects.
Knock on wood, I’m 65 and have never been bitten by anything deadly or debilitting.
Black widows are not aggressive. They are one of the few spiders I will kill because they could take out my cats, but in reality, I have them crawl on me several times - no bites. Mostly, if they see you seeing them they are like “RUN!” and take off. My house and garage used to be infested with them.