That's one weird shader for glass in your file. I would suggest using just a simple Glass BSDF shader, maybe add some volume absorption if you want to make it fancy:
You could enable caustics in the glass, background objects, render settings and the light source if you want it to be even fancier.
The model at the moment is 3 meters high, so that's one big glass. Is there any reason not to make it realistic size? I made it around 8cm diameter, 9cm tall, also applied subdivision modifier to make it smoother, made the bottom bent inwards like they usually are and added a rounded lip, because glasses tend to have them and refractions/reflections look specific way because of that. Also they tend to be a bit wider at the top. Everything should be smooth, rounded or beveled, because there are no sharp 90° edges on a glass.
It also needs something to reflect, so HDRI environment map might improve things. The looks also depend on the lighting so you could give it main light and some sort of rim light.
Maybe also set Filmic 'Look' to something other than 'None'.
These are all just suggestions, but the more realistic factors you take into consideration, the better it starts to look:
You could model it more precisely, add imperfections to the form and so on. That's the way to avoid light interactions that look weird the way I see it.