I watched and noticed how much my Bulgarian friends leave when they settled the smetka, and it's not 10%, usually just rounding it up to the nearest Lev or so, personally i think the 10% "
myth"
is for tourists in the resorts only. I also understand that many waiters/waitresses earnings are based on a % of what they take during the shift, so decide at the time what you think it's worth and don't over do it. Over tipping makes it worse for everyone else that follows.
I have myself fallen foul of "
over tipping"
in the past were at my local eatery i once didn't leave a tip and the waitress never smiled at me again (i didn't have any change that night), she obviously forgetting my previous generosities.
Common sense prevails methinks.