Excel is great, until that moment that you do something in haste over a large set of heterogenous data and cells.
And if you are doing finance, a world of pain awaits you.
edit: One other gripe about it, is if you use a macro, you can never use the easy ctrl-z out of whatever mistake you've just made.
Backups for a new analyst are few and far between. Backups for me a short while into my job could happen hourly.