At the recent L1 users conference in Colorado, we found out that a high percentage of T1 owners did not know about the BYPASS feature that's employed in many places in the T1.
The BYPASS feature is extremely useful in deciding if a particular adjustment is giving you the sound you want. It's a form of an A/B switch.
For example, if you want to hear how a particular ToneMatch preset sound on and off, you would use bypass. If you wanted to hear how a particular reverb sounded you could turn it on and off, on and off. And so on. Most effects have this valuable feature.