Here is my 100% Achievement Guide!
This is technically story related and cannot be missed but i will explain how to get said two coffees anyway.
So first up, When you crack the safe code (1546) there is a hot chili in there. Grab that and walk over to the coffee machine and click on the chili tin to get another one.
Click on the coffee machine to make said chili coffee and head left into the next room.
Closest to you you see a coffe cup, wait until the guy stops drinking and puts it down to click on it and swap the two.
He drinks it, burps fire, and gets you an item you need.
For the second one, we need a few items, so on the end there is a guy eating a lollipop. Pick up a worm that is in the trash can directly infront of you as you enter, and then click on the lolly, the worm should go on it, the guy drops it and you can now pick it up.
For the leaf, we need to do a few various things but once we have caught a fly, we are on the right path.
So once you have said fly, go back into the room with the few people in and press the fan above you 4 times so that the fly lands on the guys leafy head, and the boss whips out a machine gun and starts shooting at it.
No matter how crazy that sounds, its right as it knocks off a leaf we need.
Click on the leaf, go back to the coffee machine, and that makes the love drink.
Go back into the room on the left, wait until the boss at the far end stops drinking, you click on the cup and it swaps around, and voila finally achievement unlocks.
Go to 6:55 to see the start and what you need to get this.
Hope this helps!