A quick aside re bendiness: the physio wanted me to see a rheumatologist, which I'm very lucky work will pay for, but from a GP referral, not my physio. So I had to see my GP, who sent me for blood tests - I've ended up having three lots. She also put me on amitriptyline, which, now I've been off it for most of a week, I have to admit did reduce pain and improved how much I slept and took away my IBS but at too high a cost: I fet drugged and dopey all the time and couldn't think and had splitting headaches and nearly told my project manager to fuck off because I couldn't remember how to politely point out I was busy and now was not a good time for small talk. I also had really vivid dreams, which I'm never sure whether to put as positive or negative effect. Anyway, she let me come off after a fortnight so it's been out of my system nearly a week. I feel so much better and I am in a writing mood.
I want to talk about luck.
I trained as a maths teacher (although never went into teaching for a long list of reasons that protected me from the horrible realisation I wasn't emotionally strong enough to go into the profession I most admired), and remember being asked by one of the people training us if we believed in luck. I was the only one who said yes. Cue surprised looks, until I explained it depends how you define "luck": they were defining it in the superstitious sense, whilst I was using it as shorthand for startling coincidence or a statistically unlikely streak of events.
It makes sense to me to use it this way: I know that you can roll a d20 three times in a row and get a 20 each time (and stick your crossbow bolt right through the big bad's head for an auto kill in the first round of combat - paragraph 8 of Absalom), or reach 40 on an exploding d6 (and find a replacement for that monofilament whip the bad guys took off you earlier). The laws of probability demonstrate that someone, somewhere in space and time is going to roll a balanced d6 and get a 6 every single time - hell, in an infinite universe, there'll be a planet somewhere whose laws of probability look very different to our own because the 6 will come up every time.
I also know that, short of using weighted dice or learning to trick roll (which apparently isn't particularly great anyway), there's not really anything you can do to manipulate the chances of getting the result you want: lucky underwear might give you the confidence to approach that new friend, but it's not going magic the dice into doing what you want, so is manipulating luck the realm of superpowers?
It's certainly a very cool superpower, one I'd love. Control over chaos and entropy would be incredibly powerful and could stand in for most other powers - in fact, could be used to increase your chance of having any other power consistent with the rules of the universe you occupy. It's a power I'd be interested to explore in a supers game one day.
In fiction, I've only come across this idea a few times: the character Misadventure in City of Heroes (how I miss that game!) and Aornis Hades (spoilers in link), from Lost in a Good Book. Interesting that both are villains - maybe it's too much of a deux ex to give to the protagonist, but is interesting for them to overcome. Supporting this, the only times I can think of heroes having access to extreme luck is for short periods, such as the luck virus in Red Dwarf, or Felix Felicis in the Harry Potter series.
You can manipulate luck, and black cats and ladders have nothing to do with it. I'm thinking about Blood Bowl, where a good tactic is to force your opponent to rely on luck. You can buy rerolls and use up to one a turn to reroll a failed attempt (or if a ball is bouncing around and the wrong one of your players catches it, a successful attempt), and many skills you give players give them built in rerolls for certain types of skills, that can be use the same way. So when I take halflings to a tournament, I tend not to bother taking rerolls of my own (playing without rerolls takes practice but is worthwhile) and instead take an inducement called the halfling chef, who has the opportunity to remove up to 3 rerolls from your opponent and give up to 3 to you in each half (roll 3d6 during the first kick off of each half, and each 4+ is a reroll given to you and a reroll taken from them - it used to be a stolen reroll, so if you rolled 3 and they only had 2, you only got 2. I prefer the new way!) Immediately, you've manipulated things to fall in your favour, as the likelihood is your opponent is used to relying on those rerolls so their play style will be affected (one reason why learning to play without rerolls is so useful). You can also position your players to force your opponent to make the highest number of dice rolls you can - particularly if you can manipulate it so the types of rolls aren't favourable to them: halflings dodge everywhere on a 3 with a built-in reroll, so forcing them to dodge is less frightening for them than forcing them to block opponents, where their low strength means they'll probably be rolling two dice with the opponent choosing which outcome applies.
You can do it in roleplay games, too, playing to push odds in your favour. You might struggle to hurt a dragon, but creating a dragonbane net may at least snarl it up enough to make it easier not to die in the attempt. Lords of Gossamer and Shadow takes this further, removing the element of luck altogether and encouraging the players to find ways of bringing the odds into their favour.
In real life, we can't remove the element of chance so easily, but we can still stack the odds in our favour, or find the odds stacked towards us by chance. Research has shown that wealthy people are more likely to become more wealthy not because they are greater risk takers but because they have the money to take those risks. My intelligence, creativity and appearance are all quirks of genetics that have nonetheless given me benefits in life, along with being born into a loving, inquisitive family (although that may be tied to the afore mentioned genetic quirks). It spirals too: I got a job I love by the luck of intelligence and knowing the right person (my brother, in this case), but being in a job I love and am good at has helped me gain confidence in my abilities so that I am better able to take opportunities that arise: now I've found a path I'm happy on, I'm manipulating things to keep the luck that got me there flowing.
Optimism and pessimism also come into play. I'm generally considered an optimistic person: for instance, I feel very lucky to have a job with insurance that will cover the cost of me seeing a rheumatologist; I don't feel unlucky to have been born with a condition that requires the visit, or if I do, I do so by focusing on the parts of the condition that I like having - the suppleness, the youthful appearance, the high pain threshold - and still consider myself fortunate. My younger sister is a better example: some of her friends think she's very unlucky because bad things always happen to her but I think she's very lucky because sh's always fine. (She shared that opinion until the parachute accident: she accepts she's lucky to be alive, but the dislocated shoulder had long term repercussions on her career.) My anecdotal experience suggests being optimistic doesn't come from having good luck, but rather the perception of being lucky comes from being optimistic.
Luck is the way random chance falls. You can manipulate it, but never completely eliminate it. It affects you in ways beyond your control but the most important part of whether you are lucky or not is how you see the world.