Agree with so many listed here.
'at the end of the day'
'it is what it is'
'could care less'
Recently, I've been hearing a lot of this one:
"that's exactly right."
Thank you, friend, for letting me know that I'm not only right, but exactly right. Extremely helpful. I truly didn't mind this at first, but it's been gaining on my nerves a bit. Eh...I could care less.