Many graffiti decorate the buildings that would otherwise seem very plain:
Others have a political or politico-humorous message. For example, the first one is made near the popular patriotic slogan 'Am Israel chai'.
Tel Aviv is also full of interesting frescos that are just there on the walls where you wouldn't expect. They are most probably made professionally and commissioned by the owners of the buildings.
Some street artists, like elsewhere, choose to use stickers instead of graffiti. I fully support this kind of street art, because not only it is more dynamic, but it does not impose the author's taste on the people who must actually inhabit the space the author decides to use for his/her expression (for example, in many cities people complain about plain tagging without any drawing - it is only used by the person doing it (in this case I don't want to use the word 'author') to express some kind of symbolic ownership of the space, but has no aesthetical/artistic value for people living in the space).
When stickers survive, it means that people like them. On the other hand, if the people do not like graffitis in the spaces decorated, the only thing they can do is to resort to the authorities...
Here's my absolute favourite sticker:
Unfortunately it was removed at some point. Maybe because it was distractive to traffic, or maybe tropical rains washed it away...