Verbal pauses, spacers...
When I was younger my verbal pause was, I mean, and you know, sometimes both if I felt stress, or if I was a little drunk, (seems contradictory).
"I was going to the store and, I mean, my car wouldn't start. I tried calling the garage but, I mean, you know, all I got was one of those, you know, recorded messages."
They were absolutely horrible and I worked hard to get rid of them. I much prefer an occasional uh, but I have found that nothing is better than anything else.