Me and DH and our kids were at a large theme park a few years ago, and we found a little boy who was 4 or 5-ish, wailing and hollaring 'mam! where are ya mam?' He has lost his mother obvs.
We took him and said we will help him find his mother. We bought him an ice cream, and a little toy to calm him down, and also a can of pop. After 10 minutes or so, we came across an employee and told her we had a lost child. She radioed to a pal of hers who said the mother had just come to the front gate to say her son was missing.
The woman we were with said, 'send the mother to this wild rat roller coaster, coz we have her kiddie here. A family has found him and has been looking after him. Even though she was only five minutes walk away, it was TWENTY minutes later when the mother came (with 2 other young kids aged around 2 and 8.) She marched up to the boy and said 'for fuck's sake Connor. Where the fuck you bin?' She grabbed him by the scruff of the neck, and dragged him away wailing.
She didn't thank us, OR the woman with us (from the theme park,) and she didn't acknowledge us in any way. Me and DH and the kids and the theme park woman just stood there gobsmacked. ANYone could have taken that boy, and walked out of the theme park and she may never have seen him again. Stupid woman.
But yeah, some people! Rude, ungrateful and some are even plain thick! 
Keep the next dog you see OP. or sell it LOL!