We just completed a 1.5 week intensive manual regression test phase where we executed almost the complete set of all (several hundreds) test cases. We are in a lucky situation. Our documented test cases represent nearly 100% of all implemented features. If we achieve a 70-80% test coverage, then we get a real good picture of the overall quality of the product increment. That means, aside from the many automated tests, it's worth from time to time, doing some manual end-to-end regression testing.
While tracking the regression testing progress using a cloud based test case management tool, we were looking at the activity graph and it made us smile. It's exactly what we expected.
Last but not least, weekend is getting closer. The first enthusiasm is gone, you're starting to get bored.
You hear music from your neighbour. The caféteria gets louder. The sound of clinking glasses reaches your desk. It's time for a break, time to reboot your brain. TGIF! And now it's weekend time!