Kindness? NOT!

So, I had an interesting situation happen to me the other day.... It was Wednesday, and I was trying to purchase some items for the craft I was planning to do at Girl Scouts. The day had been busy, and nothing was going right for me. The hairstylist was 40 minutes behind on my hair cut, then the first store I went to didn't have all the items I needed, then traffic was backed up, and I nearly ran out of gas, and etc etc. It was so bad, that JB asked me " So, did you step on a black cat today, or what?" Anyway, I was at Jo-Ann's buying more supplies, and I had 20 minutes to get my stuff and make it to the meeting. I was in a serous time crunch and more than a little grumpy. When I got to the check out with my objects, in line in front of me was a 10 ish year old girl, with a pack of gum sitting on the counter. She had nickles and pennies spread out into little piles, and the checker was trying to tell her that she was $0.57 short. The little girl explained that she thought her mom had a coupon, but mom had gone out to the car already and now she didn't know what to do. So I stepped in, laid $1.00 on the counter and told the girl I'd take care of it.
Now, the little girl and the cashier are looking at me like I'm some sort of saving grace. The cashier mentions that it is "so nice of you" to pay for this little girl's gum. Yes, it looks all sweet and pretty on the outside. But, in the inside I am thinking, "Nice?" No. I did not pay for the gum out of the kindness of my heart. I paid for it because it would take A LOT longer for the little girl to go to her car and drag mom in with her coupon (if she actually did even have one) and I seriously just needed to get on my way. I paid for it because of my own selfish desire to get this kid moved on so I could take care of what I needed to take care of. It was an act of pure selfishness, and not one of kindness at all.Yet, to the little girl, and the cashier, it WAS an act of kindness.  Now, looking back, I wonder how St. Peter would mark this little act in his great book of life deeds. Does it get a smiley face because it looks like a good deed from the outside, or does it get a frowny face because it was done purely out of selfishness and self gain? What do you think?