But when it comes to software, experience has taught me that even seemingly trivial changes in financial software can have very bad consequences,

Oh man that gets me triggered!

Yeah I've definitely tried to change programs in small ways and realized I'd have to rewrite huge sections of code as the domino effect spirals outward. Damn spaghetti factories.

the "crash" from when the coffee wore off cost me more productivity than I gained from the hit.

I remember this being a thing as well for me, but I've been drinking it nonstop for so long that I feel like it all blends together now. I did drink that cup of tea today and it stopped me from feeling like I was about to start hallucinating. Small miracles. The trick seems to be to avoid drinking it every day to avoid the habit.