I'm not sure if this is the appropriate spot for this, but here goes. 
I've been wondering for a long time:
Why to us (as TFSers) congratulate someone when they make a purchase? I've seen dozens and dozens of posts congratulating someone when they purchase something - usually of a high monetary value? Why is that a reason to congratulate someone? Maybe I'm dense and though I’m happy for them, I think saying “congratulations” is a bit much. Is there a rationale for it; something I’m missing?

I've been wondering for a long time:
Why to us (as TFSers) congratulate someone when they make a purchase? I've seen dozens and dozens of posts congratulating someone when they purchase something - usually of a high monetary value? Why is that a reason to congratulate someone? Maybe I'm dense and though I’m happy for them, I think saying “congratulations” is a bit much. Is there a rationale for it; something I’m missing?
