​Imagine being in Sri Lank: the streets are quite dirty, there´s trash everywhere. You can see that the people living there are quite poor, not only because the houses could all use some renovations.
The souvenir shops in the streets are kinda unorganized and not too nice. There´s many local restaurants, serving Lankas specialties for low. Did I mention the dirt? Everything´s somehow looking the same. Especially the street dogs. And there´s way too many Tuk Tuk drivers, trying to rip you off!
Then you´re walking trough the gate, that´s separating Galle´s “main city” from the harbor city, and all of a sudden feeling like entering Europe -preferably a Dutch city.  
The streets are made of cobblestones instead of the usually used asphalt, and there´s almost no trash or dirt in the streets. Cute lil souvenir shops are to find everywhere, and they´re selling (handmade) goods that you might only find there.
The prices are also more European than Sri Lankan (=it´s fucking expensive to eat or sleep there lol), which was one of the reasons why I only stayed there for one night.
Galle is great to just walk in the streets and look around, visit the (famous?) lighthouse or watch the sunset over the sea from one of the rooftop bars.
It´s a cute little city, where almost every street looks the same, and if you don´t safe the location of your hotel on google maps, you might have two funny hours walking around, trying to find the place you´re sleeping at. In case that this happens – do NOT start randomly opening house doors, which might be your hostel. Most people are laughing their asses off when you´re telling them that you´re too dumb to find your sleeping place, plus forgot the name of it. But not everyone has that great sense of humor… Not that I experienced that tho. Never would I ever be this dumb… :D