What's up with train services reliability in Europe? In my european corner here, I always have to give this advice to people who are new to the city: do NOT use the commute train ever if the deadline is serious and absolute (you got a work interview, a flight, a funeral). Trains get stopped in the middle of the trip, get delayed, or get cancelled all the time!
The solution is to lose even more of your time (as if public transport wasn't slow enough already) and be at the station already for the previous schedule of what you'd ideally need to take. But at that point, sometimes it's just better to go a longer route by subway, or if traffic is not bad, go ahead by car for those occasions.
It's actually kind of the opposite with DB [1]: Regional trains are decently on-time, and commuter trains even more so because they usually have dedicated tracks. Long-distance trains and cargo trains are the ones with abysmal punctuality, the former because the schedules are so tight that a random passenger coughing at the wrong time can fuck everything up, and the latter because they have to yield when a late passenger train has to make up time.
The solution is to lose even more of your time (as if public transport wasn't slow enough already) and be at the station already for the previous schedule of what you'd ideally need to take. But at that point, sometimes it's just better to go a longer route by subway, or if traffic is not bad, go ahead by car for those occasions.