Get Gmod and have your friend get it too.
(works if they already have it or are new)

Then install boatloads of addons. Go to addons page and get 200-300.
Then make a multiplayer server with them.
Then when its taking forever for them to get on start screaming at them.
Repeat until necessary!

you now have no friends.
good.
all you need in life is garrys mod and garrys mod only
suck it people who have a life