Here in germany, tipping is absolutely optional, but we still do it in case we either received good service or for the sake of convenience. If you have 17.47€ on your bill, just handing out 20 is much simpler than one of the parties having to look for money.

One thing I would like to mention here is that we do have some kind of "tipping system" if you so will in grocery stores. If you are about to pay, you can say "Round it up, please". Doing so will round up the amount of money you have to pay to an even number, usually just a couple cents. This money will then be used for charitable causes, which is a very cool thing to do if you think about it.

To finish this up, I remember having watched a hilarious YT Video on the topic of tipping, I highly suggest giving it a go.