Used for the right purposes, Excel is an extremely versatile and powerful piece of software. Is use it all the time for analyzing complex financial data and turning pivot tables into really nice looking reports. I can use VBA behind the scenes to change report scenarios while preserving the formatting. Excel is great for things like that.

It's easy to get Into trouble though because eventually someone decides to keep a bunch of auxiliary -- yet somehow very important -- data in a spreadsheet. Before you know it, multiple people are being asked to maintain said data and then POOF! You now have a spreadsheet functioning as a database. It's all downhill from there.