What comes to your mind when you think of comfort foods? In my opinion meatloaf is pretty tough to beat.
Meatloaf is great.  Mac and cheese is good too.
That sounds like a good combination. I don't know how people survived without it - it didn't really make its way into cookbooks until the late 19th century.
I did not know that.  Do you mix pork and beef for meatloaf?
It depends on how busy I am or if I have the meat on hand. I've done meatloaf with lamb, pork, veal, all kinds of meat. Poultry and seafood can even be used, although that's pretty rare.
A bit of shrimp in a meat loaf would be good.  I also put a hard boiled egg in middle
That sounds pretty good too! The best thing is you can make it any way you like. In Turkish countries they serve a meatloaf-like dish with vegetables called dalyan kofte. 
Maybe I will try brussell sprouts in meat loaf.  I love them