The "I had xxx invested in the pot so I had to call...." mindset

[Ghazban]

I hear people saying things like "Well, I had $40 in the pot, so I had to call the $40 more" all the time in casinos and I even see it showing up in 2+2 posts now. Its totally irrelevant, isn't it?

Clearly, how much you've put in has an effect on how big the pot is, but whether you put it in or magical pixies conjured it out of thin air is meaningless, right? I've always thought the important thing was the size of the pot, not how much you personally put into it but I keep hearing justification for certain plays that is based on how much of the pot you put in.