finance IT can be a pretty intense. it all depends on how close you are to the business. and depending on how much your business unit is involved with real time markets and regulatory reporting requirements, your work can be very time critical.
i've had people barking at me a few times, usually because their losing money and irritable. sometimes we have network or server issues, and when the apps they rely on are slow or unresponsive, they get annoyed. you cant always blame them. they have a pretty high stress job too.
as for the hours, i personally dont have it that bad. i get in around 8, leave around 5:30.