Don't wear the same pair of underwear 2 weeks in a row; unless you turn them inside out after a week? No, wait, that comes under hygeine.

I consider "knock on wood" and other such expressions to be little more than a turn of phrase for most people — roughly meaning "I'm hoping for the best" — not truly a superstition. I might follow up the statement with a quick rap, rap, rap on my head in jest, but I don't take it seriously. I can't think of any actual superstitious habits I have, though. When I was a kid, I believed in the power of prayers and religious talismans (e.g., rosaries, scapulars, and other blessed items), but I haven't held those beliefs for a long, long time.

I just don't care anymore. I just don't do that sort of thing and would feel embarrassed if I did.

When golfing never 'talk on someone's knuckles' which means don't talk when they're lining up a shot.

Watching a hockey game and the PBP Announcer starts saying how great a player has been doing, especially the goalie. It's the kiss of death and almost guarantees him having 3 or more goals scored against him in the next minute.

I had to think for awhile. I don't have any.

I think luck has a lot to play in what happens in our lives. Luck is simply random event happenings that is outside our control. (IMHO)

Too many to mention...
And if you tell me more, I'll probably add them to my list... lol

Nice question Here are mine:

I feel reluctant to open umbrellas inside.

I always have to say bless you or gesundheit after ANYONE sneezes.

I avoid picking up coins that are face-down.

Walking under a ladder. Knocking on wood. Making a wish on a falling star. Gifting a knife set with a penny taped to it. I can't think of more.

My grandmothers both had many superstitions, my mother had some but not as many. I have none.

Take a picture of the opposing team's coach, moisten it, and stick it in the freezer. (Not me, a friend.)

That's not a superstition. That's straight-up voodoo.

I cross my fingers, I just do it without thinking!

Has getting into my car before I start the engine also something to do with superstition? I never realized that.

I have been the beneficiary of a fortunate coincidental concurrence of things on more than a few occasions. But, I have no lucky rituals.

Less and less as time has gone by.

My grandmother would go into a tizzy if am owl hooted three times, she thought someone was going to die. my ex sister in law, would lose her sanity if a bird was in the house, my caged parakeet included. Crazy!

I do the knock on woodand work at not spilling salt or breaking a mirror. Weird, never really thought about til ya posted it.

Dang... I don't have any...i know it's sad but I dont.

I won't put a hat on a bed. An old Russian superstition that means a death in the family. Silly, but I won't do it.

Isn't wearing the same outfit during two games smelly? (Of course, not if it's on the same day.)

I sometimes knock on my own head as a silly parody to the silly superstition of knocking on wood.

I say, "Good luck" to people ahead of many things, surgery, competition etc. I feel silly every time, I guess it may be appropriate if they are buying a lottery ticket? Wont improve their chances though.

I'm say "Knock on wood, "wish me luck" etc. but I don't feel like it's about the superstition, I know that's the origin. I also say "bless you" when people sneeze, I see it as being along the lines of please and thank you. I'm anti triskaidekaphobia, my birthday being on a 13th. I double down on thirteen.

I’m not aware if I do. I guess I wet the toothbrush prior to toothpaste application, but I don’t think any superstition is involved. Idiosyncratic? Maybe, but not superstitious. The term ‘luck’ is probably shorthand for the phrase ‘random events’, at least when I use the term. “Hey, Generic Human X, good random events today!” just doesn’t have the same ring to it as “Yo, good luck, dude”. If I told my friend the latter, I really meant the former. As far as a ritual to influence the outcome of events to be encountered in the future, unless you count smoking a blunt before everything I do as superstition, I say no. However, smoking does make things bearable. I can say that not because of the misclassification of perceived cause and effect, but because of the physical, observable, and testable attributes inherent to the physical nature of the process.

I have the weirdest most terrifying fear of Hats on Beds... It is so bad that literally every time I put something down my mind asks "Could this be used as a hat? Could that be used a a bed?" It comes from watching Drugstore Cowboy as a teenager. Matt Dillon's character has this fear and one scene his beautiful girlfriend puts a hat on a bed and he freaks out. That night she overdoses and they have to stuff her body in the crawlspace of the hotel and leave her there. I guess since I was 13 at the time and wanted a really hot girlfriend and didn't want her to die I could never let a hat onto a bed. Funny (not funny) story is that a couple years ago the girl I was dating gave me a hat, she threw it on the bed and I freaked out. The next night she almost died. I took her to the emergency room and they found out her intestines had spilled out and she had only a 30% chance of survival... 30% chance she would live but have colostomy bag for the rest of her life and a 30% of recovery. She survived but had to spend a month recovering in my apartment and use a walker and a had all these tubes coming out of her... I won't even tell the part about the CIA and Seal Team 4 connection... it's all true. NO HATS ON BEDS!