Where my head gets sore

I think the kids are going to wonder what's wrong with there parent if they don't know the difference between there and their.  I can cope with sometimes leaving space between commas and text and sometimes not, but the spelling teamed with the lack of any other grammar is just making me want to bash my head on something.  And then another comment by the same poster!  If you can tell me what it actually means I would be very grateful.

There again.  It would have to be one of the most commonly misspelt words on the Internet, along with your/you're.  This one also has the gift of odd comma spacing, but I'll give the poster a break and blame that on the device used.  It can be hard focusing on grammar when you are writing with your thumbs, I guess.