Overthinking
I tend to overthink everything I do, eg. when it comes to approaching strangers. My mind ends up talking me out of it by predicting what might happen, even though those predictions never occur. I've realized over time that I should just go for it and not think too much. It's that easy – just go do it.
I've noticed I even ponder before going outside my building, and often convince myself not to go out. I'll make excuses – there'll be too many people, bad weather, or that it'll be stressful. However, I've never regretted going outside post hoc, and most times I end up enjoying it even vastly more than I thought I would.
Hell, today I intended to go to see a movie but accidentally misremembered the start time and went out too early, so I walked around and ended up visited some shops and parks. It was awesome! I think if I keep going outside, even when I don't feel like it, I'll eventually condition my mind that there's nothing to fear and that I'll enjoy it.