Do not compare your kid to other kids. When kids are tired they get cranky, loud and defiant. This is not the time for discipline. Just get them out of the situation they are in and let them crash. Toys Babies don't need a zillion toys Don't waste money on those ugly black and white mobiles for infants.
Age ranges on toy boxes are usually a good guide.
Noise making shape sorters are cool. It's OK to pick toys you would like to play with too. The swim vest system with little foam slabs that you remove one at a time really works. Day care, after school programs, summer camp, etc. Modern lice are immune.