Green trousers sat on the "absolutely not" shelf in my head for years, filed next to dungarees and anything with a slogan on it, because the one pair I owned at twenty three was the colour of a snooker table and made me look like I was heading to a fancy dress party as a hedge. What changed was trying on a pair in a much darker, muddier shade in a changing room with terrible lighting, expecting the worst, and actually liking what I saw.
That's the bit worth knowing before anything else: shade changes everything with this colour. Olive, khaki, bottle green, anything with grey or brown mixed through it, those wear like neutrals and go with almost everything you already own, including black, navy and most prints. The brighter end, anything that reads as grass or emerald or that snooker table green, is a much louder decision and needs the rest of the outfit kept plain, because it's doing all the talking on its own. A deep forest green in a slightly heavier fabric has been the easiest one I own, it's gone under jumpers, under shirts, with trainers and with boots, and never once looked like it was trying too hard.
Where it falls apart is in fabric choice more than colour. A thin, shiny green fabric can look a bit cheap and a bit costume-y in a way that a thin black trouser just doesn't, so if you're nervous about the colour already, don't also gamble on a flimsy fabric, it stacks two risks on top of each other. And if your work or your life runs mostly on neutrals and you rarely feel like standing out, a bright green might sit in the back of the cupboard looking guilty, worn twice and then forgotten.
Fit is where most green trousers actually go wrong, not the colour itself. Because the shade draws the eye, anything slightly off in the cut gets noticed more than it would in black, so a waistband that gapes or a hem that pools gets amplified. Go a size down if the pair is in a stiffer cotton, since those don't give the way jersey or a softer twill does, and check the length sitting down as well as standing, since a lot of green trousers I've tried run slightly long in the leg. After a few washes the darker shades have held their colour far better than the bright ones, which can fade at the knees first, usually right where you'd notice.
A good dark green pair, once you find the right one, tends to get worn more than you'd expect and complained about less than you'd fear.