Use a tissue? No snot on your fingers then
Would you spit flem into your hand and drink it back up? Assuming your hands are clean. You swallow mucous involuntarily, doesn't mean you should eat your own dried snot intentionally
If you want to boost your immune system why stop at snot? Anything with bacteria will be good for your immune system
Blowing my nose usually doesn't get the job done and picking your nose with a tissue is a lot less accurate than using my nimble fingers. More importantly, I don't always have a tissue. Unless you walk to the sink every time you cough up phlegm, you probably swallowed loads of it and hey, it isn't that bad. Though no point in spitting it out first if you're going to swallow it. Snot is designed to be ingested and bacteria insulated by snot are weakened, giving your body a chance at developing antibodies against a bacteria in a weakened form. Other sources of bacteria do not do this, which is why ingesting snot can be especially beneficial.
So let's make up the list. I find nose-picking the easiest solution to pesky dried up shit up my nose, which looks bad as well if anyone happens to gaze down your nostrils. Your body is designed to get rid of snot by ingesting it. I find the taste of boogers pretty good, perhaps because your body wants it to be ingested. Eating boogers helps your immune system. If you can see past your shortsighted cultural taboos and have a pragmatic view on this you'd find that eating boogers is not so weird. Taboos are dumb, masturbation and homosexuality were taboos once until people got a more pragmatic view, who knows, eating boogers might be next in line to acceptance. I feel no need to do it in public, but I see no reason to lie about doing it.
Okay, this is gross, I would never shake a hand with any of you.
What makes it gross and why would you never shake a hand with any of us?