[nickname]

I understand that aldol reactions are useful for the introduction of a new C-C bond in a molecule, but what are some of its limitations?

So far I have:
side products
comple mixture of products
ketones can undergo base-catalized aldol additions, but their equilibrium is unfavorable

Do my answers seem reasonable? Also, are there any other limitations of aldol rxns, including crossed aldol aditions?

Thank you so much for your help

[azmanam]

in a crossed aldol, there is a possibility of 16 different products due to other limitations of the aldol.  Can you identify why 16 different products could form?