I could go on for some time about how the cities differ, but I wanted to really think through what made these cities similar. And in many cases these similarities are common throughout continental Europe. Regardless, these similarities made it comfortable travelling from one city to the next. And why I tell people all the time that if you have travelled to one European country don't freak out about another. Many of the customs are similar!
First off a small European Union Primer. The EU consists of 27 "states": Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and the United Kingdom. HOWEVER, not all of these states have adopted the Euro and still retain their original currency. Czech Republic is one of these countries. They still have koruna (crowns). To make things more confusing some countries use the Euro but AREN'T part of the EU (Switzerland for example).
So enough history what did I find was similar? Well these may not stick out for some and I'm sure there are tons more but the following three were enough different from the United States that I took notice.
1. Restaurants are for visiting and enjoying the meal. Service is relaxed (read slow as molasses in January). You MUST ask for your check or you will sit there for as long as you want. Also in the Czech Republic they will keep plunking down glasses of beer until you tell them to stop or ask for the bill. So learn quickly how to ask for the bill in continental Europe or your meal times will last longer than you thought!
For a type A American this actually gave me anxiety. Even when I KNEW they were waiting for me to ask, I was antsy wondering what was wrong (Had I been rude? Were they sick of Americans?) So take heart, travellers! It's not you. It's them. And you and they are doing nothing wrong!
2. Put the money down on the counter. Don't hand it to them. And they will give you your change on the counter. Don't reach for it. One would think this wouldn't be so attention garnering, but one woman jumped when my son reached for the change. LOL. there is always a little tray by the register. Use it.
Public Transportation is reliable and frankly preferable to walking. Both cities have tremendously punctual tram lines. Both have subways, but Prague's is less prevalent. Use the trams instead. Multi-day tickets in both cities cover the use of trams and trains in the city and Berlin's includes buses as well.
So these three stick out the most, but I'm sure there are more. For the most part the cities are so different. Prague was saved by war. Berlin was decimated. Prague is all about the past, the history. Berlin is about the now, and the future. Prague is relaxed and calm. Berlin is moving and brisk. Everyone has asked which one I like better and that is like asking if I have a favorite child (which by the way is NOT the oldest after this trip....KIDDING!). They are all different. They all have their own unique talents and opinions. And their own annoying behaviors. But all of them have a place in my heart....just like these two cities.