Good one, thank you for the post.
(even though, I got it right with inconsistent thought on this "This may take significant time on large tables." and was wondering if the DB is online and users connected to it via application and the application performance would reduce in that particular time frame - and then thought; wait - why would they drop index on the main DB, such activity is done on mainly DWH in the maintenance window with very less users connected and the impact would be very less... and then thought may be this was the case of 2008 R2 and below and may be 2012 and 14 have bettered in this area.... well!!!)
The first and the hardest SQL statement I have wrote- "select * from customers" - and I was happy and felt smart.