I suspect it's more to do with the optimisation of the method. For example, calling List.Count in a tight loop is much faster than IEnumerable. Count. I don't

I suspect it's more to do with the optimisation of the method. For example, calling List.Count in a tight loop is much faster than IEnumerable. Count. I don't use resharper so don't know if it watches out for this, but no doubt there are plenty of other examples.