Do you work in sales? Probably not I think.

Salesforce automates sales as well as customer support and was the first to do this effectively on the SaaS model. It's dominant among sales teams in mid-sized companies. You can be up and running in a few days including training. I find the interfaces a bit "enterprisey" (i.e., complex and clunky) but would not dream of having a sales team that did not track sales through SF or something similar. Personally I like the visibility it gives you into the sales pipeline--at any given time you can tell exactly what your current revenue is for the quarter and project into the future as well. It's very helpful when running a company.