In Bulgarian, the word for "thank you" is "благодаря" ("blagodarya") but people often fall back to a simple "мерси" ("merci" - the French word, yes) for transactional thank-yous.
I'm not really sure whether that's because "благодаря" is reserved for sincere, heartfelt thanksgiving or because the word is just too long to say very often.
Since 90s (and all the American movies) most people switched to English "sorry" instead of the French "pardon" for casual "I'm sorry". The original "przepraszam" is still mostly used for more meaningful apologies. And "pardon" is still there if you want to sound old-style casual.
And yes, part of it is - "przepraszam" is longer and sounds more "dignified". The thinking goes "if you're really sorry you should work for it".
Italy seemed a lot denser to me so I bumped into people a lot. I quickly got habituated to say "scusi" which is Italian quick apology.
There isn't really good formal quick apology in Poland. Pardon or sorry sounds disrespectful if you are apologizing to older person. You need to go with full "przepraszam".
As a Pole you probably know where I'm going with all this...
When I came back to Poland and bumped into older lady in the shop I quickly said "sku..!...przepraszam"
In polish "sku.." is how some of the expletives start.
Do you know why?