When i went to Vienna the first time, i went to a nice coffee place, waiters were really kind, i remember one, his name was marco a nice man we talked a lot, he was telling me some things about the city and his life, anyway, when i was on the table an old man came to me and asked me if he could sit with me (the place was full) he said he was only going to drink a cup of coffee, i didn't see the problem so i said yes, immediately the waiter came and told him he got him a table, the guy rejected his offer saying he wanted to sit with me that he was ok there, so the waiter got angry and made him stand up of my table and kicked him out of the place, i got really scared, so the waiter explained me that these kind of people look around for girls that are alone they give us something (a drug) and then we end up giving them all our stuff, pretty much we get robbed. They are called gypsies!
I think one of the best ways to get to know ourselves and meeting new people is when we travel solo. We enjoy every single corner of the place we are, we appreciate everything, socializing is easier, people is curious to meet us, to know our stories, we make new friends from all over the world, etc.
Everything sound perfect, but we have to be very careful. This is my story thank god nothing bad happened to me but there is bad people everywhere we go.
This is why I recommend you to watch Berlin Syndrome, a great thriller.
Thank goodness you were made aware before a problem presented itself.
Yes you need to be very careful. Strangers can drug you with rohypnol in your drink.
In Brazil and South America there is one even worse called scopolamine which all the need to do is get you to breath it.
https://www.biopsychiatry.com/scopolamine/borrachero.html
https://www.drugs.com/illicit/rohypnol.html