Am I the Problem or Is It Them?

I don't understand why people are the way they are. 

Why do they change so much? 

Am I the only one who feels this way? 

Are people always like this, or has something shifted? 

Sometimes, I feel like I’m not cut out for human relationships at all. I’d rather be alone or adopt a pet than deal with toxic people. 

Or maybe, am I the toxic one here? It's really disheartening to witness such envious attitudes.