What do you do when you meet a guitarist for the first time to give the impression that you really know about the guitar? Why you say, "Let me see your guitar." You hold it for three seconds as if guessing the weight of a frozen turkey, hold it up to your face for two more seconds and say:
"Hmmm. It's nice enough. The action's too high. It needs a set-up."
Why do this? Because it is the go-to, old stand-by critique that has more of a chance of being correct than not and it makes you look like an "I've played so much- I'm such a pro- I've seen it all" authority. You haven't played one note on that instrument and already you know it just isn't quite right. Wow, you must know your stuff!
You are also very ignorant, arrogant, and just parroting what you have heard other guitarists say who probably don't know what they are talking about either.
The action, or height of the strings away from the fretboard, is adjustable (in most cases). You can set it anywhere you want. Most people prefer it on the low side, but that is not required. It is true that in the past, cheap beginner guitars often have had terribly high action. Does that mean a high-end one with high action is in need of adjustment? No. There are reasons why you would want the action high.
Now, you've told someone they need a set-up and you'd be surprised to hear they just had the guitar set just that way. Perhaps their role is rhythm guitarist in their band. They use a heavy strum technique and find when the action is low the strings contact the frets. Perhaps they have raised their pickups and the magnetic pull is dragging on those metal wires we call guitar strings. They may have raised the action to find a balance between ease of play and sustain. Perhaps they play other styles of music you didn't know about where they prefer high action and just want all their guitars uniform- acoustics and electrics.
Did you know anything about what they play or how they play before offering your opinion? No. But you'll argue that guitar manufacturers list a specific millimeter height for strings in the manual or that your guitar tech whom you constantly, mistakenly refer to as a luthier(!) told you that there is a specified height that they consistently use. Sure, there has to be an as-good-as-any general-use starting point. Have you ever sat in a new car in a showroom? The seat isn't set all the way forward or all the way back. It is in a generally good place for most people. But guess what? Your mechanic isn't going to tell you, "Oh no no no. This seat is too far forward. You need to set it back about three inches." You know why? Because it isn't his car and he isn't driving it. Just as that guitar you critiqued isn't yours and you aren't playing it.
What you might have said, if you even knew anything about not just guitars, but guitar playing is, "Your action is too high ...for me."
But you didn't because you wanted to look like a big-shot and...you don't know what you're talking about.
Some very high action examples:
Jazz: Freddie Green (on his road guitar as high as 1/2 inch off the 12th fret!)
Rock: J. Mascis (for whom Fender/Squier makes an artist model guitar (that they ship with the standard string height, of course)).
Shredder: Michael Angelo Batio (who plays contrary to the belief shredding requires low-low action)
And by "you" I mean guitarists. Those of you that don't play may think a guitarist would be a good source for accurate answers about music and gear. Nope. In many areas you will find that they all simply repeat the same misinformation they have always heard themselves, but with added authority. However, the music companies manufacturing their products must know what's what, right? Wrong again. In particular, let's look at Fender in today's example: a vintage (or vintage style) amp.
This is what everyone and their mother would tell you is a Fender tweed amp. You could ask 500 people what this is and all 500 will say, "a Fender tweed". Fender will also tell you it is a tweed amp. It isn't, because that isn't tweed. I don't mean it's synthetic. I mean it literally isn't tweed. That's TWILL. This isn't knit picking. Tweed is a specific fabric and it is not on this or any Fender amp. The people who will say, "It's the same thing- who cares?" are probably the same who say they don't care if they use the word literally when they mean figuratively. I can guarantee you that they would, however, throw a fit if while they had their amp recovered the craftsperson ran out of twill halfway through and finished the rest of the amp with tweed.
This isn't a great sin on the part of Joe/Josephine Guitarist. It is easy to understand the mistake. How often does a person, specifically a young guitarist, encounter tweed or twill- especially today? Back in the '50s (Leo) Fender labelled things with words he thought he knew on more than one occasion and we are stuck with them today. Someone should have stepped up and pointed out these errors, but they probably didn't want to correct the boss and perhaps in the case of the amp fabric it was someone in sales and marketing who described these as tweed covered. If so, there are mistakes we know are Leo's fault that we'll address soon enough...