Tweaking pregnancy test

I just dont get it.. I mean i do get it yall want to be pregnant but its not going to happen if you tweak it or not if you are you are, if you're not you're not.. Its just seams like it makes it harder doing it then it really being negative, it just seams kinda messed up getting peoples hoped up and then it not being what they want :/ i just dont get why people do it.