This is something I've been guilty of in the past, and I still feel the urge to let my mind go down this path occasionally but I've found life is a lot easier when I summon the will to stomp it into submission.
Lots of threads on here are started by hikers asking questions like "this rain jacket vs. that rain jacket" or "this sleeping bag vs. that sleeping bag" or "best pair of boots" or "boots vs. trail runners". I think if you're really into hiking you have the urge to equip yourself with the best gear possible, and that drive leads us to going on outdoor supplies websites and comparing the sleeping bag with a 4.6/5 star rating with 567 reviews to the one with a 4.7/5 star rating with 334 reviews, and inevitably asking 2,000 other people which one they'd choose.
Before I get to my main point, there's no substitute for buying stuff in person. You get to look at it, not a picture of it. You get to touch it, feel how heavy it really is, and explore every inch of it. Not everyone lives near a Cabela's or EMS or Dick's, but if you're planning on something like a thru hike I honestly wouldn't see an issue with making something like a 3 hour drive to a store like that. That being said, there's only 2 items I think you really NEED to buy in person, shoes and a pack. You need to put both on your body to see how they feel. You could probably chance it with a pack that absolutely everyone screams and raves about (and those exist), but unless you've already found a brand/model of hiking shoe that you know works for you, you have to go to the shoe department and walk around in the things for a few minutes.
But I digress. Let's say for example you're torn between 3 different rain jackets. All have great ratings and reviews from plenty of people, all are comparatively priced. OHMIGOSH which one do I get??? Honestly dudes and dudetts, it really doesn't matter. They're all rain jackets that have been tested and reviewed from here to the other side of the world. They're all made by reputable companies. They're all gonna keep you dry. Choose the one that's $10 less then the other two and buy the damn thing
You can say the same thing for any other piece of gear. The best rated sleeping bags are all gonna keep you warm, I promise you. Watch the youtube videos for setting up the tents you're stuck between, choose which one looks easiest to you and go for it. If it's a good tent (which you can tell by reviews and ratings) you don't have a good chance of picking one that's mysteriously hard to use by you in person even though it looked awesome on the web.
Just my $0.02