Not a big worry BMB.
Humanity has many presumptions that run contrary to good science:
#1: We're the top dog in the universe
#2: Earth is super-special and a wonderful planet
#3: Life either exists only on earth or is rare.
#4: The vast distances of the universe would keep anything from reaching us, because even five light years would take them five years, so nothing ever visits us.
#5: Obviously nothing exists because nothing has talked to us, and we're special, damnit.
#6: All the things that have been here are explainable via religion, or dimensions, or something to preserve the common beliefs in elements 1-5.
The science is showing:
#1: There are over 3,000 incidents a year that cannot be readily explained, and many incidents that are so well-validated in telemetry, signals, and witness observation that they cannot be discounted by any explanation. Tic-tacs being the most famous of them all. Our own government recognizes there is a level of technology that surpasses anything on earth, and it's often around.
#2: Earth lacks all sorts of materials, minerals, alloys, etc., some of which we're aware of existing in e.g. asteroids within our system, and some of which we know we don't have but exist only in theory because we don't have them.
Subnote: Why would anything really want to "take earth" if it's the equivalent of a Detroit ghetto. The places that anything wants to be, they would already be. Some real estate isn't "worth it". These incidents are not new, they've been going on for a very, very long time. If anything wanted earth, they already would've built here. Nothing wants to stay.
#3: Every test for life is essentially positive on every rocky world in our solar system, with the exception of Mercury, which we haven't really looked at. Life is so prevalent in earth that it exists in extreme temperatures, extreme ph, extreme chemicals, and extreme depths. There's really nowhere it isn't on earth. The presumption of "we're the only planet with life that we know of" is an incredible bias that has been invalidated every time we look. The converse statement "We haven't proven that life isn't on EVERY rocky world" is actually just as honest. The truth is most likely somewhere in between, but preliminary evidence is that life is very common "out there'.
#4: People who believe that the universe is vast don't understand time dilation at all. While there are certainly methods of transportation we can't even conceive of, the fact remains even from conventional travel, the faster you go, the shorter the distance becomes (or alternatively, the faster you get there). If you go light speed, you, the traveler, transit the entire breadth of the entire universe in a single moment. That's one of many reasons you can't go light speed. Time only passes for everything else - the universe ages around you in that single blink of a moment. However, fractional light speed conveys the same benefit, fractionally. And more importantly, our science has proven that instead of traveling through space, it's far more ideal - and possible even within our lifetimes - to expand and contract spacetime to "move" your bubble through space itself, exceeding the issues of light-speed travel because you aren't traveling at all - space is. Even our primative asses are not that far off from reaching nearby stars. And certainly we're within a thousand years of reaching all the stars in the milky way if we don't kill ourselves first.
#5: There are so many instances that are clearly superior technology from other species. Sorry, but Parsimony has proven to be the root of our best science; catering to cognitive dissonance has not.
#6: We can't even converse with highly intelligent species on earth in any extent (Elephants, Dolphins, Whales, Octopus, etc.). We're early in our technology journey and already developing many methods of communication that transcend vibrating air. It's retarded to think that other far-more advanced species #1: Give a crap about "taking" with us and #2: That belief stems from the first one in which we think we're something special; and #3: That they are event possible of vibrating air in a way to communicate at all, much less care to. E.g., we are not capable of communicating in the same way that anything else does. If life is endemic to the universe, then any travelers within it have seen an utter-crap-ton of it, and we're incredibly irrelevant to other species.
The big point here, BM, is that yes, shit is out there. But it's also a lot older than us, and ol' Earthy is not special enough for anything to give a damn. Best not to piss whatever they are off (there's been a few attempts that failed dismally, mostly in Russia and Iran), but they are probably about as interested in Humanity as a person driving by on the interstate is in stopping and conversing with a Prairie Dog. Even when that prairie dog flings poop the drivers just ignore it.
Why are there so many events? Who knows, but based on the most well-documented and irrefutable cases, I'd speculate the majority of the time it's simply resources - heavy water or H20 as they are typically water focused or water collecting. Then they depart this detroit gas station on off to their actually desired destination, you know, the equivalent of Cabo or a Florida beach, instead of a burnt out ghetto with shitty winters.
Nobody REALLY wants to live on earth, not even people. Looking at you Musk, and all the volunteers that want to live on a cold, dusty asshole of a planet instead.