It is most definitely not a waste of time. Getting to know your neighbors is very valuable as it gives you both a frame of reference for times of emergency and need. For example, if you want to borrow something, or need a ride because you have run out of gas, or if you see someone acting suspiciously, or you want them to keep an eye on your house while you are away.
Having said that, it is also important not to take advantage or be taken advantage of. So, we try to strike a balance between being a friend and being a nuisance. Most people manage this well.