In terms of performance converters (nothing factory) a loose converter will give the feel of a slipping transmission just cruising around town. Generating extra heat. This is why it's important to use a large transmission cooler to combat the high temperatures created by the loose converter. They don't achieve lockup until a high RPM (whatever they are designed for) and until then, they are loose and "slip".
Modern tight converters can give the best of both worlds. They can flash to a given RPM on launch, yet allow very streetable cruising at very low RPM, due to their ability to lock up at lower RPMs like a stock converter. Then, when you launch, they flash to the desired RPM that they were designed for. You can easily have a converter that will stall (flash) to 5500 RPM and yet drive around town docile as a stock converter with no slipping feeling at all.
The problem is, no one believes it that's never had a modern converter. Lots of people are still stuck in the 70s and 80s frame of mind when it comes to converters and you cannot tell them a damn thing when they ask about it because they slap will not listen. That's why a handful of us are growing weary of explaining it over and over and over again. Some people simply will not get it, no matter how much you preach it. It's like
@crackedback says all the time, the converter is THE single most important piece in an automatic equipped street or race car and to me, it's more important in the street car, because THERE is where it must do both. Cruise on the street at a reasonable RPM and launch like a race car when needed. Some people will just never believe that both are possible with the same converter. But that is the fact.