Even when Filioque, Papal Primacy and possibly indelibility of Holy Orders are usually considered the main points of disagreement between the Roman Catholic (RC) and Eastern Orthodox (EO) Churches, there is an additional significant area of disagreement comprising the issues related to the teachings of EO St Gregory Palamas (1296-1359). Below I list the four points of disagreement in this area, in both their Catholic and Orthodox versions.
C1. God is Being from itself, subsistent Being, absolute fullness of Being that is infinitely "above" the received, contingent, limited being of creatures.
C2. Absolute divine simplicity: God is his essence. Each divine Person is the divine essence.
C3: Sanctification or deification: union with God by way of two inseparably connected gifts 
- uncreated grace: the indwelling of the three divine Persons, which is specially attributed to the Holy Spirit only by appropriation. “This wonderful union, which is properly called ‘in-dwelling,’ differing only in degree or state from that which binds the blessed to God in eternal happiness, although it is without doubt produced by the presence of the whole Trinity … is attributed in a peculiar manner to the Holy Spirit." (Pope Leo XIII) 
- created grace (sanctifying or deifying grace): the product of the foundational re-creative work (the "new heart" and "new spirit" of Ez 36:26, the "new creation" of 2 Cor 5:17 and Gal 6:15) carried out in the soul by the Holy Spirit, to whom the work of sanctification is specially attributed. Quoting RC St Thomas Aquinas, sanctifying grace is "a permanent quality placed by God in the very essence of the soul" (i.e. it is an accident and not a substance), which enables the soul to be inhabited by the Holy Spirit in a unitive, vivifying mode (Ez 37:14), i.e. in a mode that causes the soul to share in divine life, in divine nature (2 Pe 1:4). 
C4. Beatific Vision: saints in Heaven see the divine essence.
O1. "God is being and not being." (EO St Gregory Palamas)
O2. There is a real, ontological distinction between divine essence and divine energies. God is his essence and his energies. The divine essence is the cause of the divine energies, which are uncreated. Each divine Person is the divine essence and the divine energies.
O3. Deification (theosis) is union with God through his energies (uncreated energy of the Holy Spirit = uncreated grace), and not through his essence.
O4. Saints in Heaven do not see the divine essence, only the divine energies.
In my view the less difficult issue of the four is point 3, where the disagreement, if we leave aside the essence-energies issue, is mostly a matter of emphasis. While EOs have placed emphasis in uncreated grace, i.e. receiving the Holy Spirit, RCs have placed emphasis in created grace, the work of the Holy Spirit in the soul. But RC's do believe in uncreated grace, i.e. divine indwelling, and EOs would most probably agree that the Holy Spirit does some very important work in the soul. The main disagreement in this point is that which is a direct consequence of the essence-energies distinction, as EOs believe that only the energies of the Holy Spirit interact with the faithful, and not the essence.
RC-only saints are prefixed "RC St". EO-only saints are prefixed "EO St".
 Fr. John A. Hardon S.J. "Course on Grace - Part One - Grace Considered Extensively - Chapter II. What is Grace?"
 Fr. John A. Hardon S.J. "Course on Grace - Part Two - B - Grace Considered Intensively - Chapter XIII. Sanctifying Grace and the Indwelling Trinity"
 Fr. John A. Hardon S.J. "Course on Grace - Part Two - A - Grace Considered Intensively - Chapter VIII. Sanctifying Grace"