Approaching a tram/bus stop, you can always tell from a bit of a distance if the trash can is full, because when it is the immediate area surrounding/beneath it is a sea of cigarette butts. Even then, it seems, while most smokers will NOT take their butts with them and dispose of them properly elsewhere, they will still not just litter everywhere and anywhere, instead "placing" their butts next to the full trash can, maybe to make a statement that at least they tried...
The amount of butts littered in the downtown area with all the historic buildings and historic cobblestone streets - but also very busy with most of the bigger item shops there - is extremely low by now, virtually non-existent in most areas, not just because there are ashtray-ized trash cans there too, but also because there is city officers regularly patrolling there, making sure people don't litter in general, beggars/musicians stick by the rules, bike riders don't use the pedestrian only areas, etc. Those patrols will fine you for your flicked butts, EUR 35 on regular streets and EUR 80 when you litter on harder to clean cobblestone IIRC.
This is very true and highlights how addictive nicotine is. We’re willing to light these things on fire and breathe it into our lungs but are disgusted by the remnants and feel a compulsion to immediately discard it.