1. The most important one. Do not EVER spend your spare time reading blogs like mine. You might be permanently addicted for life.
2. Never ever ever spend your spare time folding up washing. Your mother might see you doing it and helpfully give you more washing to fold up.
3. Don't spend your spare time looking bored. You might be noticed... and then you won't be bored any longer.
4. If you want to be bored, at least try to look busy. That way your boredom will go under the radar.
5. Don't spend your valuable spare time on the telephone. Use the phone only in the direst of emergencies. I've found that phone calls almost always take way longer than anticipated.
6. Do not ever waste time explaining complicated principles to someone who won't understand them anyway.
7. Try your hardest not to spend your spare time helping people. They aren't grateful enough for your time and efforts, and you always finish up feeling grossly unwanted.
8. Never spend your spare time doing what you really want to do. Chances are you'll: a) botch it up somehow (in which case you'll feel awful you did it), or b) do a really good job (so you'll be really annoyed you didn't start doing it sooner).
9. Don't spend your spare time reading boring books. If you must waste precious time on a few scraps of paper sewn together, at least read a good book.
10. Don't spend your spare time feeling thankful. Thankfulness only makes you happy and everyone else happy.