The actual time spent bleeding is only ten minutes or so, and there’s little discomfort after the needle is done being inserted. But be honest, the entire process from start to finish includes:
commuting to/from the donation point
waiting for available staff to get you through the intake process (eligibility questionnaire, BP check, blood iron check)
setup (the staff goes and gets a collection bag, sample vials, and other supplies)
the actual bleeding-into-a-bag part of the process
recovery (sit at a table and have a beverage and snack to ensure you’re OK for the commute home)
When I go to donate, it’s going to take about 90 minutes out of my day (and I’m OK with it; I’ve donated over 80 pints now). My employer used to host on-site blood drives, which dialed the commute down to a short walk. Even without that though, they have a generous paid time-off allowance of several hours to go and donate off-site. I recognize that other folks may not have such generous employers, so they would either need to take unpaid leave or take time out of their after-work hours to go donate.
AIUI, blood transfusions, even when matched for basic blood type, incur some risks due to other details about the donor blood and host blood. Artificial blood that could reduce these risks and ensure an inexhaustible supply would be a huge breakthrough.
A coating which is impervious to spray-painted graffiti. Any spray paint that hits it would just bead up and roll off, like water off a newly-waxed car.
An appetite suppressant which is not speed or has any harmful side effects.
That’s feasible.
A microphone, a speaker a power source, & a modulator .
Samples the vacuum’s noise, then generates a counter-noise, out of phase with the vacuum.
Viola ! Silence.
I don’t know if it would “really improve life”, but since I was just toasting some bagels:
A toaster that has some kind of optical sensor or camera in it, so you automatically or manually monitor how much you toast is actually toasting. Toasters have “settings” that are supposed to stop the toaster at the point of doneness you want, but they’re not very precise, and different things toast at different rates anyways, bread vs. bagels vs English muffins vs frozen waffles.
What I want is something where I can tell it, “I want ever item to be this particular shade of brown”, and it pops up when it hits that point, whether it takes 30 seconds or 3 minutes.
Modern cell phones have sensors and computing power sufficient for LIDAR. Produced commercially this would provide photogrammetry, topographic photography. A cell phone could function as a security device by identifying the presence of humans or animals perhaps even identifying them individually. Hikers and climbers could photograph a scene topographically. Archaeologists could plot a dig with a click. It could do the same for a home project by measuring and graphically plotting a room, garden, or tree house.
When the first iPhone came out, I expected them to functionally become Star Trek Tricorders by now. All kinds of sensor systems are smaller and cheaper now than ever before. You should be able to make a hand-held device which takes all kinds of local-level scans by now.
Drinking straws. The plastic ones are an environmental problem, paper ones are too flimsy. Naturally occurring straws like bamboo aren’t economical because they require too much processing. We could genuinely use a just-durable-enough straw that would decompose after disposal.
Sounds too top-down social engineering to me. Efforts to recreate faux-village life have a dismal track record.
A dishwasher that is actually useful. I was at a hotel where, at breakfast, there was a machine that made pancakes by squirting batter onto a heated conveyor belt that pushed out a finished pancake at the end. That is what I envision: a machine that you feed the dirty dishes into, it uses hard spray for scrubbing, a short soap phase and a hot rinse, giving you clean (albeit wet) dishes out the back end, while somehow wasting a lot less water in the process and making a lot less noise.
There was some idea that quasicrystal alloys could do this, and one version was marketed by Sitram Cybernox. Unfortunately they suffered from excessive corrosion in regular use.