Download five chord/lyric charts and odds are they will all be different.
I'll some times use a chord chart as a starting point, but that's it.
This, or the other thing I too often see is that someone transcribed a chart and posted it on a Usenet group back in the early '90s, and it's been reposted an infinite number of times on many different chart sites without anyone ever bothering to correct errors made in the original transcription. And the thing is, these charts were often written by people that are no more expert than the people now using those charts (just like a lot of YouTube "instructional" videos), but the users now treat them as gospel simply because they're written down. I tend to be somewhat skeptical of all charts found online.
Lyric sites are just as bad. I've gone through many, many sites looking for the correct lyrics for a song, and in one instance ("Sonic Reducer" by Rocket From the Tombs) ended up emailing the person who wrote the song, who set me straight (none of the sites, or the many recorded cover versions, had the correct lyric).

I like to tell guitar players, "Pretend I'm a piano player, and tell me what key you want to play it in." They usually still have no idea.
