(3) Cost basis matters whenever you sell an asset, whether it's a house or a stock or whatever. You can get sucked into partnership cost basis calculations simply by buying certain mutual funds that are structured that way.
(6) Diverse activity means income in more than one jurisdiction. People who travel a lot for work can end up filing with dozens of states. A real hoot.
2. What am I going to deprecate, my Civic?
3. Despite being in a healthy tax bracket I don't know what this is.
4. See #3
5. Snoozefest
6. Diverse activity?
7. Yeah I think most of your objections apply to the minority of people who actually hire a CPA to do their taxes.
The bottom line is, for the vast majority of people (even people with interesting W2/1099 incomes like me) you could do your taxes on a napkin if you enjoyed a bit of paperwork/math pain. Again: the IRS already has basically all of this info. What gives?