Here's a joke I heard once at a music academy:
How do you keep a pianist from playing? You take away their music sheet.
How do you keep a guitarist from playing? You give them a music sheet.
This joke rings oh-so-true because it highlights a key point for those of us who tried to learn guitar by ourselves: the typical amateur guitar player doesn't know how to read music, and (s)he doesn't care about it. Somehow they manage, but how they do that remains a mistery to me.
Typical guitar tabs (those you buy at a shop or download from the internet) contain therefore little more than the lyrics for a song and the points at which you are supposed to switch from one chord to another. This works pretty well for your left hand, but how about the right one? Should I just move it up and down? And at which speed? "Well", says the guitar book, "you should just do whatever feels natural". This is of course useless - what am I, the song whisperer? What if nothing feels natural? Do I just sit there in silence?
Let's take the following example, which I borrowed from Ultimate-guitar.com
RHYTHM FOR INTRO AND VERSE: D G A E|--2--2-2-0-2---2-3-2-0-2--3--3-3--0--0--0-0-0-0-0---| B|--3--3-3-3-3---3-3-3-3-3--3--3-3--2--2--2-3-2-2-2---| G|--0--0-0-0-0---0-0-0-0-0--0--0-0--2--2--2-2-2-2-2---| D|--------------------------2--2-2--0--0--0-0-0-0-0---| A|--------------------------3--3-3--------------------| INTRO D G A [play twice] VERSE 1: D You'll say G A D we got nothing in common G A D no common ground to start from G A D G A and we're falling apart
This is actually a fairly complete piece: it shows the lyrics and notes (lower half) along with an attempt at explaining how should the strumming (i.e., what to do with your right hand) be performed. But here's the thing: it's not clear at all which strokes should be "up" and "down", nor the duration and silences between them. You cannot derive rhytm from this information, which is pretty bad for a section titled "Rhytm for intro and verse". And here's an extra fact: the "D" section should actually be played exactly the same as the "G A" section, but good luck discovering that from this notation. This is a known bug of guitar tabs, and yet I have several books with songs that don't even include such a section, either because they don't care or because they realized it's useless.
This is one of those very few problems that is currently solved by, of all things, Youtube. It's not too hard to find a "How to play Breakfast at Tiffany's" video tutorial, where some dude will spend some time showing you slow motion strumming, so you can play the whole thing. But how come youtubers have fixed this problem so fast, while guitar books have remained the same for decades? Why isn't everybody complaining? My theory is that the typical amateur guitarist picks up a guitar, downloads one of these tabs, fails at getting anything out of it, and quits guitar forever saying "guitars are hard".
I don't really have a good solution, because any attempt at formalizing the strumming will undoubtedly require some knowledge about rhytm, and guitar players seem to hate that. Perhaps that's how we ended up in this mess in the first place. Or perhaps there's a super easy, totally intuitive method that I've always missed for one reason or another.
But then again: how can a method do any good if it's never taught?