Why do so many of us see imaginary 2nd lines?

After 8+ years of TTC. Every. Single. Month. Without fail, I “think i see something” on a HCG test. Literally ... every. Single. Month.

Why do some of us just ALWAYS see a line? Is it wishful thinking? Is it different vision seeing more of a shadow than others can see? Shoot - I saw my friends BFP before she did. It took her 2 more tests to actually be able to see her 2nd line.

Any theories ?

Just spent the past 5 minutes SWEARING I saw a 2nd line on a very obviously BFN and it got me thinking.