I've been asked to put up a commiseration post for parents of 18-month-olds.
Remember why 18 months is so crappy: massive sleep regression (sometimes lasting for several months), the 6-month disequilibrium phase, often movement stuff (running) , often teething (molars), and an enormous mismatch between their receptive language and what they can actually say. So you have a kid who wants to do everything themself, has a zillion thoughts but can't get them out so you can understand, isn't sleeping well, is physically and mentally out of sync, and has very little control over anything.
It's not a good phase. But It Gets Better. Usually 21 months is a turning point for development, language production, and sleeping, so it all starts to come together and they're much more fluent in everything and in a much better mood.
Who needs to vent? Who has It Gets Better stories?