You'd have to be really, really good!....and you ain't.
LV426 is a little overly emotional, but her logic was sound. Just mistaken. As you already probably know, the LW Looney who is truly looney is Katzgar. Like B&T, he's outside the normal parameters of human behavior.
Not preaching to the choir (well, maybe a little), disagreeing is normal. What's not normal is when people become so emotionally upset that all they can see is their own point of view and never understand others can be equally sane but with differing POVs. Katzgar can't see it. Neither can the TD twins, Matt, and, of course, B&T. This indicates a mental problem.
In many cases, like Matt and the TD twins, advanced age is part of the problem. Their minds are going and those mental failures magnify any minor personality quirks into something that needs treatment.
B&T is 40-50s which is too young for most elderly mental issues. Katzgar is the same. They still have a chance of a normal life with treatment...which they won't seek unless the law forces them to do so.