Do you want a shambling undead creature to walk next to you? Imagine the smell of rot and decay following you wherever you go.
It would be a bad idea to have drinks with a Zombie. If he hands you a drink, you might find a piece of his finger fallen into the glass. Not that he could say sorry or anything, a zombie is well known for is inability to speak “uuurgh, aaargh, uuuuh”.
Also, if you ever travel around with a Zombie, make sure you use a helmet. Zombies love brain, and would not hesitate to go for yours. And this would really become awkward if you bring him to a party. Easy to say, he would not be the life of the party… perhaps the death of it.