Re: Are harsh tones ever desirable?
Personally, I use harsh ugly tones as an effect pretty regularly. Sometimes, a terrible, thin, ugly sound, is exactly what's needed in the context of a certain song. Some bandpassed nastiness sometimes just sits perfectly in a mix (live or on record), when the bass, drums, and vocals are supposed to be the center piece...That said, it's great as an "effect" sound...but as a primary sound, no, that's not good.
Blues Junior's aren't really incredibly bright, harsh sounding amps from my experience. If your's is incredibly harsh, when using the bridge pickup of your tele, at higher volumes, then either something is wrong with the guitar, or amp....or ya have the tone controls set poorly for your situation...or maybe you just don't like tele bridge pickup tones? Like others have said, the stock speaker isn't too great...but even with the stock speaker, the BJ shouldn't be incapable of good tones.
Question...when eq'ing the amp...do you set the eq to sound best on the neck, or bridge pickup?
If you're setting it up to sound great with the neck pickup...then you're gonna end up with an overly bright bridge sound, especially with a Tele or Strat. Just like if ya set it up to sound great with the Bridge pickup, you might end up with a muddy neck tone. Thats just sorta how it goes alot of the time. Tele's w/vintage style pickups are especially bad about this.
Having a relatively bright Bridge pickup, and a somewhat dark/muddy neck pickup (vintage styled tele neck pickup), it's really difficult to get a great balance between the two. You'll end up having to decide whether a great neck tone, or a great bridge tone is more important...cause its next to impossible to have both. Unless you swap the neck pickup for something brighter (Strat pickup, Twisted tele neck, Don Mare Stelly, etc...), or Swap the Bridge for something Darker (JD, Ant II, 1/4 pound, APSII tele, Even a lil bucker etc...).
Also, since no one else asked...are you plugging straight in, or running any effects in your signal path?