What are your favourite fillers?
I usually use, 'you know', 'really?', 'I mean'... and you?
And what fillers do you hate? You know, sounds posh, outdated or whatever.
Dan Smith is true that too many fillers is not only a suffering for a listener but also a deduction in the mark of a test. Supposedly a good speaker had better eliminate the usage of fillers as much as possible. For a non-fluent speaker, that might be a huge challenge not to use fillers while they are speaking, but it can be reduced to the least degree by constant practice.
I consider even some native speakers cannot exempt using fillers at all, but indeed, too much redundancy is very bothersome for a listener to concentrate on.
Toastmasters is a self-help club for people who are trying to improve their public speaking ability. (It is mostly a U.S. organization, although there are chapters worldwide). Toastmasters teaches speakers not to use filler words and noises. When you give a talk, three judges take notes: the timer, the grammarian, and the "ah-counter." The timer checks whether your talk runs too long or not long enough. The grammarian watches for grammar and English usage problems. And the "ah-counter" literally does that: counts all the ah's, um's, er's, well's, like's, really's, other meaningless sounds or words that are just used to fill gaps. Toastmasters teaches you try to eliminate them completely. I think Toastmasters is right.