It's also sociologically interesting because Sava/Lazar/Vianu people (or, generally speaking, people who went to good Bucharest high-schools, it's probably the same for other big-ish Romanian cities like Cluj or Timisoara) are more "aware" of the high-school they went to and they generally tend to keep friends with their high-school colleagues for way longer (my so's boss went to Sava and he's still active friends with his former Sava colleagues 25+ years after finishing high-school). Like I said, we don't have that thing in small-ish cities.
I say it's interesting because I kind of noticed the same thing in this thread with people who went to prestigious schools in Moscow (#57, #2), they tend to remember fondly said schools and some of them kept closely in touch with their former colleagues.
It's definitely a thing even in smaller cities with good highschools. Reunions for 10,20,30,40 years are very common and attended by all, including teachers still alive, etc.
There was no rivalry between Sava and Lazar 30 years ago, except for the Cismigiu park. They were in the top 5 schools in Bucharest, but there was no direct competition, they were all considered good places to study and kids used to choose based on the location and other preferences. Lazar had easier access to Cismigiu and lower admission grades, Sava was in a strange neighborhood but a nice, larger building, MF1 (Vianu) was smaller and harder to reach from some places, etc. They all had good teachers back then, no longer these days.