We rely on pregnancy tests for a lot, when you think about it. If you spent more than one or two months trying to conceive, or have had fertility difficulties, that positive pregnancy test can be a truly historic event. Likewise, a negative pregnancy test can generate a ton of negative emotional energy.
You might not realize it after taking (and tossing) handfuls of failed pregnancy tests, but a pregnancy test doesn’t always keep its result over time. You might take the pregnancy test and, in as little as 24 hours later, the positive result line (and probably the control line) can be gone.