Author's note:
I really wanted to include Hector DING-DINGDINGDING-DING Salamanca, but I couldn't think of a good match for him in Half-life.
Also, I've found Gatorade me, bitch to be a very useful saying in life. For example:
"Would you care to try any of our fine wines?"
GATORADE ME, BITCH!
"Paper or plastic?"
GATORADE ME, BITCH!
"Cover your left eye and read the smallest letters you can"
GATORADE ME, BITCH!