How afraid should I be of getting mugged?

In the area and I was out for a walk in a neighborhood when I noticed two young men riding bikes past me, on the street where the house I'm staying in is at(south Seattle). I kept walking and was going to continue my walk, but I decided to turn back on the off chance these two would turn around and try to jump me.

Well, I turn back, and one of the guys is coming back in my direction(red alert), I don't see the other anywhere. He gets on the sidewalk I'm on(red red alert), riding towards me. I step aside and he stops and asks me for the time. I look at my phone and say it's one'o'clock(in the afternoon), but I kept walking as I did so, not looking back. Turned into my house about a ten second walk later.

Am I being paranoid to think that if I stopped, the other guy was gonna pop out from somewhere and take me by surprise while the other distracted me?

A few days back, I came across another young guy walking down the sidewalk, carrying something with both hands like it's heavy. I see him looking around, seeing an older woman gardening nearby, and then he looks back at me. He steps to the side and waits for me to approach(I see he's holding a large bottle with white stuff in it) and asks me how I'm doing. I say fine, and then he starts to ask me if I've heard of some game and I cut him off with "Can't talk, I'm busy" and walk away while he starts laughing behind me. I feel like best case scenario he was gonna try to get me to give him money for some bullshit kickstarter project that doesn't exist.

Am I being paranoid to think that I just narrowly avoided two potential muggings? I'm completely unarmed, not really in a position to get a gun at the moment, but I'm wondering if I should invest in a pocket knife or taser.

EDIT: You know the more I think about it the more I feel like there's no reason at all for that biker to ride down the middle of the sidewalk towards me when he was just riding on a perfectly empty road. Fuck him for trying to mug me or at the very best being intensely spatially inconsiderate.

EDIT EDIT: The fact that I was wearing earbuds probably made me look like more of a mark in both situations too. I hate that I can't go for a walk listening to music but it feels like it might be a necessity to not wear earbuds while out and about.

EDIT EDIT EDIT: You know, it's funny, I shaved off my goatee a couple weeks back because with job interviews for white collar work there's plenty of stuffy weirdos who will discriminate against you for having facial hair. I feel like I blended in a lot more when I had that goatee. I'd never had any encounters like that when I had it, and I think that there's a real chance neither of the above interactions would have happened if I were still goatee'd. Makes me look older and meaner and grungier. Without it I am a chubby-cheeked dimpled boi.