Public vs. Private Behavior

Do you ever wonder about people's behaviors?  I mean if someone's openly mean, how mean are they at home?  I mean I feel like I can be a grouch sometimes, but when people are just commonly like that in public (and we're usually more comfortable with our behaviors at home) how bad is it at home?

At swim lessons tonight there was a lady that had her grandkids there.  I know because I heard one of them call her nana.  Anyways, They were probably about some of my kids' ages.  I'd say 13, 8, 5 and 3ish on all of them.  The 13 yo was a junior lifeguard and was helping the lifeguards teach.  The 8 year old just finished her class before ours started and the other two didn't have class at all.  As soon as I got there grandma and 13 yo were fighting.  One apparently wanted to go home and then they just got into a stubborn match and the grandma kept yelling at her to shut up.  The 3 year old was being so patient and being pretty well-behaved for his age but she ended up yelling at him too.  He was tearing at one point, but wouldn't cry out lout, poor little guy.  Grandma pulled out some medications for the 8 and 5 yos to take and was yelling at them to shut up because they were trying to tell her how much they had to take and she was trying to read whatever their mother wrote.  Apparently, one or both were supposed to get 1/2 and she couldn't break them.  So she proceeded to yell 'you mom is full of f**ing sh*t'.  I got so tired of listening to it I had to go to the opposite side of the pool to watch the big kids for a bit.  I couldn't take it anymore. 

I came back to my spot to watch Chelsi and smiled at the little boy sitting behind me and he just quietly smiled back.  I was relieved that she was the grandma and not the mother and hopefully they're not with her often by the way she treats them.  I've never heard shut up so many times in my life.  They really were pretty well-behaved little kids.  Especially, the two youngest.  I don't think my kids would have ever sat that still that long.

I guess some people still surprise me.