Pet Peeve - Overpaying

We all have pet peeves, and one of mine is overpaying... the amount doesn't matter, €1-€100, it all drives me crazy.  Being frugal can be good and bad, in this case bad... why, I just can't let go.  What brought this all up, €3... yeah, you're reading it right, I overpaid by €3 and it's going to nag at me for days.  People like me will hold on to receipt for a year, just in case (my junk drawer at home is embarrassing).  So how could this have happened?  It has to do with an online order that I happened to mail back 30 minutes before finding the item on sale somewhere else.  You're probably thinking, you can easily send back an online order, what's the big deal.  Well, I ordered two toys for Christmas, then it turned out that my niece actually wanted something else more.  No problem, I kept the game and sent the art studio back (original invoice & box included).  Next stop after the post office, I happen to see the game for €3 cheaper.  Now what, all I have at home is a scanned copy of the invoice... seriously, what am I am going to do, buy a box, waste the gas to return to the post office, in the mean time using up the €3 I am trying save.  No, I'm not.  Instead I'm going to grumble about it.  I'm going to kick myself in the butt for trying to be efficient and get the toy off my hands immediately.  I'm going to let it fester, tell myself I could do even better watching out for sales.  Wow, I'm just a little crazy.  Inevitably, it all evens out though.  The other day to save a few euros, I returned a pair of footed stockings for my daughter because I found them cheaper and 2 for 1 at another store.  So I guess I should be happy I caught the last sale to make up for missing this one.  Any of you have silly pet peeves that will make you go out of your way for something?  Oh yeah, and the game that I'm complaining I overpaid for, I still originally bought on sale.  And in my husbands words, cuckoo!

Bye! Dag! Adios! Namaste!

:) Danica