When my boys act up I try to remember they are constantly growing and changing. They have bad hormonal days, just like I do. It doesn't excuse behavior but helps me remember they have bad moments. Maybe your younger one feels left out, mine little one does and tells me so...says everyone talks over him (which is true, sadly), so I'm trying to be more sensitive to his needs. Parenting is hard at times, tomorrow might just be a better day for all of you - I hope so.