I went to Europe last August and promised I would return next year, only to break it barely a month later when I managed to snag an award seat on the 2nd ever AKL-JFK Qantas flight. I had a good trip in the US although it seems I'm the only one who hasn't gone to Europe.
Last year, I only found major crowds where there were major monuments like Westminister Abbey where there were queues snaking outside - the way I got around crowds there was to come back first thing on Sunday. The only place where the whole 'town' was crowded was Brighton Beach and that was the annual pride event was on there - the upside was that it was easier than it otherwise would've been to find the train going down there. In going to Europe, I did like the escape from the short winter days in Australia and everywhere I went it was between 20 and 30 degrees.
My previous trip to Europe in 2018 was in late November, it was a sort of celebration from finishing university trip, and I loved the Christmas markets in Oslo, Norway - I got there right in time for the first snow of the season. I'd love to go back to Europe one winter and see the Christmas markets in Germany given how good everyone says they are.