Seeing how much people change weirds me out

Title kind of says it all, but it mainly just relates to friends or at least people who I used to be friends with. It's honestly crazy when I stop talking to someone then find them again years (hell, or even months) later and they're a completely different person, whether it be beliefs, personality, identity, or some combination of all those. Meanwhile I've just stayed basically the same since forever, only really changing my online name/handle when it comes to sort of "major" changes in my life, or at least when it comes to major changes online. Then I'm just left thinking "what in the world happened to you?"

Honestly when I see how much people change I just get sad because they used to be so much better than whatever state I find them in now. Not ALL the time mind you, but it just feels like people completely lose what made them unique and more like "themself", if that makes any sense.