<human>: I thought I'd surprise my gf of 5+ years for Valentine's Day this year with an expensive bag she's been eyeing for a few months. 

I went to the store and bought the one she showed me online and was aware that there is only an 'exchange' and no returns. 

I surprised her when we both got home from work today and her eyes lit up like a kid in a candy shop when she saw the shopping bag and the wrapped box. 

She opened the box carefully, still with a wide smile on her face, but when she took out the bag, she took 1 look and coldly said, "this is a mistake, this is the wrong one. I don't want it". 

At this point, I'm getting frustrated because this is the one she showed me. When I asked her what was wrong with it, she replies, "I wanted the bigger one." 

When she said that, I stormed out of the apartment in frustration and anger. 

She's done this one time before in the past with another expensive gift, but this time is even more frustrating because I thought I was being thoughtful but I guess not. 

I still love her very much, but I can't stand what seems like selfish and greedy behavior on her part. Any advice would be great.

Can you give me a shortened version of the text?
<bot>: My girlfriend immediately rejected her Valentine's Day gift because I picked the 'wrong one'. Now I'm out a lot of money and frustrated at our relationship.