In musical terminology, Improvisation is a particular artistic device where you embellish/expand a preexisting theme, usually into a more elaborate presentation, e.g. Jimi Hendrix's version of the national anthem. It's not babbling some crap that you may or may not have just made up.
The real problem here is that most of the people that talk about music arent qualified to have an opinion about music. Its like a couple of yuppies arguing about cars without knowing diddly squat about gear ratios, compression, torque, or swirl and roll. It just makes you look like a bunch of ........ing idiots babbling on about your own opinions.