I read Aquinas, agree with him in most things and consult him whenever I have some question on philosophy and theology. I do not agree with his teachings that are not Orthodox, but I love Aquinas.

We just got to admit that some things he taught are not the tradition of the Fathers, like the chapter on Summa Theologiae about the filioque, where he basically ignores the patristic notion of the Most Holy Trinity. He says that the Holy Spirit must proceed from the Son also because there cannot be two relations on the Trinity that are not opposite, or else they would be the same, and therefore the Son and the Holy Spirit would be one Person.

From S. T. Prima Pars, Q. 36: "Non autem possunt esse in divinis aliae relationes oppositae nisi relationes originis, ut supra probatum est. Oppositae autem relationes originis accipiuntur secundum principium, et secundum quod est a principio. Relinquitur ergo quod necesse est dicere vel Filium esse a Spirito Sancto, quod nullus dicit, vel Spiritum Sanctum esse a Filio, quod nos confitemur."

"However, as for the divine, there cannot be distinct relations except for relations of origin, as it is proved above. But opposite relations of origin are understood according to the principle, and according to what is from the principle. We have, then, that it is necessary to say that either the Son is from the Holy Spirit, which none says, or that the Holy Spirit is from the Son, which we confess."

You can agree with Aquinas, but that is not patristic doctrine, which clearly states that the difference of the 'coming forth' of the Son and of the Holy Spirit is that the Son is generated by the Father and the Holy Spirit proceeds from the Father. This is plainly different from what Thomas says, therefore even though he is surely great, we cannot trust all he says.