If you're going to use tools, be careful.
Tools vary in size and ability to hurt you from a teeny brass safety pin to a worm-drive saw. Bigger ones will do more damage faster, and you may find that shock keeps you from noticing the damage early enough to abort the process. Kitchen knives, rotary cutters, sewing machines, awls, graters, rasps, sanders, anything driven by a belt or motor, razors, utility knives, and fishing line (not to mention horsehair) can slice you before you know it. Some tools also hurl projectiles at you if you aren't careful enough, and those may either cut, puncture, or embed into your skin/the meat underneath. So be careful.
If you're going to work, be careful.
If you go to shut the truck door, be careful.
If you're going to cook, be careful.
If you're going to build, be careful.
If you're going to clean up your worksite or your after-meal cook site and dishes, be careful.
If you go to comb the cat, be careful (no stitches, but yes, I have blood poisoning too

If you're tired or it's been a long day or you've had too much caffeine or you're pithed as all get out because your boss / building partner / coworker /significant other is too busy being a jerk to notice you're working, or if you're on the next-to-last beer, be careful (and for the love of all that's holy don't drive!!!).
And if you weren't careful, WASH YOUR HANDS!!!
Make damned sure the doctors, nurses, EMTs, or helpful friends with towels (or neighbor kids with milk for knocked-out teeth ...) WASH THEIR HANDS BEFORE YOU LET THEM NEAR YOU, too.
The fan blade was a new one. Where the antibiotic-resistant staph germs came from, on the other hand, was probably the doctor's (much bloodstained) white coat in the ER, for my dad. One shot of penicillin wasn't anything like sufficient -- and antibiotic-resistant infections really do give you chills, fever, and an altered mental state; the swelling and red streaks running toward the chest, alas, didn't wash off the way actors do them in the movies.
(I was luckier. Squirt-bottle-peroxide and gobs of Neosporin, and three days later it's nearly as good as new. But the day after the bite, it looked like a purple sausage with a fingernail embedded in it, and I couldn't bend any of the knuckles.)