I didn't mean to ruin the little girl's dream

Something happened on Sunday night that made me realise that there are more that matters than me myself.
I feel like a total idiot.
I shall describe the courses of event.
It was about 820pm and already i was anticipating for my release of work at 9pm. A Indian family of 3 came by. Dad, Mom and daughter. They were interested in a considerably cheap keyboard. I was keen on closing the deal so i painted a brilliant picture of how useful and good this keyboard would be as an investment.
Whatever they requested, like delivery and a free stand, i agreed to it.
DAMN was i selfish.
I wasn't even sure about the delivery process and the FOC of stuffs that come along with the keyboard and i freakin' agreed to them blindly.
Dad took out his credit card and yay! i close the freakin' deal, only to realise that i was wrong. There were no free delivery and stand.
Little girl was asked to play the keyboard the whole time. She seemed rather unwilling with the frowned eyebrows and pouted lips.
I had to correct myself infront of them and they were upset. I couldn;t explain myself. All i did was apologised.
To no avail of course, eventually they left.
I was kinda mad both at myself and them. Myself: becos i got everything messed up. Them: becos i felt like i huniliated myself. I mean i've apologised the whole way till they left unhappy!
Then there were approximately 10mins before i could leave. I spaced out in my own thoughts, taking a ride back down memory lane.
When i was younger, maybe around 10.
I've always liked the piano. Fascinated by how it could be played, and the beautiful melody that one could play based on their mood. I've always wanted to be able to play out tunes that could keep my emotions accompanied.
My dad used to ask me if i would wanna learn the piano. Of course i want to but i said no. I guess i was afraid that i am not good enough for the piano. Know what i mean? It's hard to explain why i think that way.
So when he brought me to stores that sells piano in it, he never told me to try out the piano cos he always thought that i didn;t like the piano.
I always looked on at the piano intently, esp when there would be other kids who would sit on the piano bench and hastily play out a nursery tune. Even nursery tune would make me go wide eyed-opened jaw. no kidding.
I never had a piano.
OMG, It was Dejavu. And it daunted me that i had ruined that girl's dream. A dream that i killed even before it could sprout out to its potential being. How sucky was i? I never meant for it to end this way.
Now i'm sincerely remorseful for my greed.
I'm sorry.