curtain call

In Germany the applause after a theatre performance or a concert is usually long, the actors have a pre-written routine who walks out in front of the curtain when and with whom. If the audience hated the evening they will applaude as often put in the reviews only "politely" for several minutes. During some especially emotional performances you will get some "Bravo!" or "Buuuuuh!".
Normally the curtain shuts, the last note is played and the last word spoken and there is a small moment of silence - partly insecurity on the part of the audience if it´s finished now or not, partly to breath out and let the just experienced sink in a little.

In the UK this is quite different. Normally the applause has a strict routine as well and doesn´t take longer than 2-3 minutes. There can be some excitement expressed through "Wooooo" shouting and feet stomping (which in some of the dilapidated theatres in London can get very scary, I´m only reminding you of this). There are exceptions from the rule as just experienced in The Royal Albert Hall after a Prom concert were the audience got quite exstatic and applauded for well over five minutes.
Another difference - last word spoken and: boom, the clapping starts.
No moment for reflection, no nothing.

So, if you are British and visit a theatre or concert hall in Germany - don´t get bored and clap rhythmically along if you really liked it.
If you are German then don´t be surprised or count it as dissatisfaction with the performance when the applause is short.

edit: As Alice quite rightly pointed out - the same goes for cinema. In the majority of cinemas in Germany the light stays out the first few minutes of the end credits, in the UK (and outside of arthouse cinemas) people storm out straightaway and don´t give a shit about the credits.