'Slacking off' sounds bad. However, enjoying more of your day with the time you saved by doing your job in a clever way is definitely not a bad thing. Times like that are what makes a human's life rich. If you exaggerate, it could be called laziness, surely. However, people only become mature when they are able to balance work with enjoyment. In short, if all you care about is your job, you're not fully mature.
There wouldn't have been a bright future if I had died or I had been the only one to survive.