I’ll generally lock my door if I’m going anywhere at all, although I don’t always for groceries because A) I try to haul everything in one trip, anyway, B) my apartment complex is pretty small and I can easily see my front door from my car, and C) apart from when the lock is busted, the only people who can even get into my stairwell are the 3 other apartments that share the stairwell with me. None of my *immediate *neighbors are the least bit threatening; in fact, I barely know them at all. The newest one I’ve never even seen. Best not to take risks, I understand, but rarely do I even need to make a second trip at all. If I’m taking out the trash, which is often further away, I absolutely lock my door.
You need to read The Gift of Fear immediately.
The sentence above is why.
You’re implying that you’re being a bit silly with your concerns about this guy. That you’re overreacting. You’re not. It sounds like you’re actually under-reacting because you don’t trust your own assessment of the situation.
By the way, are you sure the guy’s sister even lives in the building?
I’m sure they do.
Some people are better at it than others, apparently.
Analyzing your statement, it appears you think the creepy guy is more at risk from the OP than vice versa. I think that’s unlikely.
Regards,
Shodan
If you’re going to be schlepping around pepper spray, might I also suggest an air horn? Portable, remarkably disabling to get a blast right in the face and the noise attracts attention so if the creep gets you cornered somewhere you can blast him and have a reasonable expectation that somebody’s gonna hear and at least look to see WTF is going on. Don’t think there’s any laws you’d be running afoul of carrying one, either.
Agree though that you def should not dismiss your feelings about the guy. Humans evolved to know stuff without having to reason it out and it’s a good idea to pay attention to that. Worst case scenario is that you unfairly malign some harmless person INSIDE YOUR OWN HEAD which doesn’t impact them in any way. Feel free to feel squicked out, it’s not hurting anyone.
To me, sounds like the brain-damaged or Down syndrome people I used to work with. That is, completely and absolutely harmless, taught very simple rules for relating to people, easily pleased with a smile and a handshake.
I wasn’t there. I’m only responding to the description of the behaviour given in the OP.
If this man has Downs Syndrome he should have guardian(his sister, maybe?)
She needs to be notified about what he’s doing. This is another reason to report this to the apartment Management.
Who knows he could get himself hurt or robbed if he goes up to the wrong people.
Again I say, report it, ASAP.
If he’s mentally challenged you should be able to pick that up from the conversation.
Buy a cheap clip on cameraso you can photograph the guy and report him to building management and share the image with family/friends.
If he’s mentally ill you have no idea if he’s harmless. Reporting him is not just in your best interest it is for others who live there.
when you’re going to your car have the key in your hand and the same when you go to your apartment.
Learn to defend yourself.
If he’s totally sane, you have no idea whether he’s harmless, either.
Plenty of people who are of normal or above-normal intelligence, neurotypical, and considered fully sane have committed crimes of violence.
It doesn’t matter if he is sane, insane, or mentally challenged, or whatever. He’s harassing the OP. The man needs to be reported and possibly visited by the police. IMHO
I’ve heard that book recommended so many times in women’s spaces. I’ll be adding to my amazon cart 
I’m not 100%. I’ve certainly never met her. I don’t see how he’d have any other reason to go in that building unless he knew someone there (while it’s technically the same building I’m in, there’s no way for him to get to my stairwell unless he goes through a different door (which, if it’s closed securely, he can’t do because he doesn’t have a key for it).
While I honestly don’t get a mentally-challenged vibe from him (he does make eye contact and his speech doesn’t sound ‘off’ in any way), I’m no psychologist, and I’m a little uncomfortable trying to give him either label. Like a few people have said, it doesn’t really matter either way.
Small update: I haven’t seen or heard from the guy since Sunday, so at least that’s good. I am still looking at getting at LEAST the pepper gel, and get used to carrying it around on me. I’m also going to contact the realty company and ask about posting a sign just inside my building that’ll remind people to close the door SECURELY behind them, so it actually locks (right now, if they just let it swing shut, it will not latch). It’s for all of our safety, not just mine.
Not sure about cameras, since it sounds like they don’t work great through windows (?), and I can’t place them anywhere outside or in the stairwell.
You guys have all been so helpful and supportive. I wasn’t sure exactly what kind of response I’d get here, and I haven’t been on the message boards real long, although I’ve been reading Straight Dope itself for years. You guys are an awesome bunch, I just want you to know 
Kovitlac - Have you talked with the management of your apartment complex yet? If he tries to engage one more time, make sure you do that, and in some method that leaves a document trail.
StG
If you wear earphones you can both pretend you don’t hear him and take his picture with your phone at the same time. Plugging in earphones to your phone will cancel the ‘clicking’ sound the camera on your phone makes when you take a picture.
My college student daughter wears earphones specifically to ignore people (men) who try to engage with her in weird places (like when she’s just walking down a sidewalk). Most of the time the earphones aren’t even plugged in to her phone.
If you do have to engage with him, just give him a firm “No” even if it’s not an appropriate answer to whatever he is saying.
You don’t have to say anything else at all; no answering questions, no explaining, no justifications, just a firm “no.” Repeat a time or two if necessary, and then no more.
It sucks that you are kind of stuck there while defrosting which gives him an opportunity to try to engage with you.
Is that problem improvable at all? I’m in south Texas. We don’t have that ‘defrosting’ thing here.
Does the car need a repair or does it have a feature that allows you to start the AC before you come out to the car (mine does)?
I think people are thinking he’s mentally challenged because he’s not picking up on Kovitlac’s non-verbal cues that she’s not interested…
But there’s a good probability he’s just an asshole.
That door needs to be fixed, in addition to or in lieu of sign. Please report that.
The clicking sound is optional and can be turned off in the settings–it’s only there by preference so you know you took the shot. I take lots of pics of animals so the click will spook them and I always turn it off first thing when I get a new phone.
More dishonesty from you, so much so that it amounts to a false accusation.
There is a brand of camera called Yi, which one can position inside a window without having to worry about glare as long as one goes into the settings and turns off the infrared light AND the indicator or status light. One can watch (and listen) through the camera in real time via the phone app. They’re not expensive, but one needs wifi. Also, keeping the light off (or screened by curtains) does away with any reflection difficulties. The camera may be set to motion activated and takes a 32-gb micro-sd card. I have an Android phone, so I’m not sure if it’s compatible with Apple.
There are stationary and mobile models. They record audio as well as video.
In analyzing BOTH of your statements I’d give each of you a nitpick score of 72%
You extended Shodan’s statement into something he didn’t intend to say and he did the same to you.
Sorry for the continued hijack. Add my vote to the crowd that says the OP should be proactive in this situation by buying some defensive deterrents and notifying the authorities, both apt management and police.
Seconded. And people are notoriously awful about following through on reminders like this one. Some don’t give a rip, and others get so used to the sign, they stop consciously seeing it. And it’s not the responsibility of the tenants.
Don’t be too eager to let management off the hook. This isn’t a tough fix for them, and it’s a reasonable request.