If you have the LTR "Excellent groupie", you always have a great outing. My sim would get a moodlet for "great time out".
Friendship levels go up from a great time out. Aquaintances can become good friends and friends become best friends.
To increase relations with your boss and co-workers, this is an excellent way to do it.
I have my sim take her aquaintances to dinner, then after eating to a club for dancing. It's better than a party.
One note : some of them go home with you afterwards (those that are not too tired) and then leave in their car from your home. If you want, before they jump in their car you can invite them inside.