Who is disqualified from serving as an executor?

Section 78 of the Texas Probate Code states:

No person is qualified to serve as an executor or administrator who is:(a) An incapacitated person;(b) A convicted felon, under the laws either of the United States or of any state or territory of the United States, or of the District of Columbia, unless such person has been duly pardoned, or his civil rights restored, in accordance with law;(c) A non-resident (natural person or corporation) of this State who has not appointed a resident agent to accept service of process in all actions or proceedings with respect to the estate, and caused such appointment to be filed with the court;(d) A corporation not authorized to act as a fiduciary in this State; or(e) A person whom the court finds unsuitable.

Fairly straightforward except for the catch-all "unsuitable" provision in subpart (e).  I'll explore that standard in future posts.