Spend two hours fixing old but surprisingly efficient ac unit I had sitting in garage. 

Add spray insulation to crumbling foam wall inside (would need to tear all sealant out if I opened it again)

Carefully install in office window- mount bar to studs in inside wall so ac unit can't be pushed in or pulled out. Cut foam to fill holes, seal cracks with tape, perfect draft free install. Installation takes a solid hour. 

Turn it on

One minute later

DAMMIT I FORGOT TO OIL THE FUCKING FAN. 

*Have flashbacks to fixing people's laptops then discovering that I had forgot to plug in trackpad or side ports on final inspection*

Guess I'll just live with it.