Fire meeting fire
Neither party has to be talked into anything. Enthusiasm is returned rather than moderated, plans are made at speed and both take pleasure in the other being impressive in public.
What a doubled element removes is the counterweight. Earth is missing, so the practical arrangements are handled late or badly. Water is missing, so neither is quick to notice that the other is quietly hurt. The pairing runs warm and can be surprisingly inattentive to what is actually going on underneath.
Fixed against mutable
Leo is fixed and Sagittarius is mutable, and this is the real division. Leo commits and expects the commitment returned in kind. Sagittarius commits sincerely and revises when the situation changes, which it does not regard as a breach.
So the recurring argument is about constancy. Leo counts what was promised; Sagittarius counts what was intended at the time. Neither is lying and both are correct about their own conduct, which is precisely why the argument does not resolve on its merits.
The Sun and Jupiter
Leo is ruled by the Sun, which is identity, and Sagittarius by Jupiter, which is expansion. Both are traditionally warm and neither is subtle, so the tone of the pairing is generous rather than guarded.
The difference is where each looks. The Sun refers everything back to the self and wants to be recognised. Jupiter looks outward at the next thing and forgets to acknowledge what it left behind. That single asymmetry accounts for most of the wounded pride in this pairing.
Where it grinds
Attention. Leo requires it and Sagittarius distributes it freely to everyone in the room. A Sagittarius partner is not being unfaithful when it does this, and it is regularly accused of something adjacent.
Money is the other place this shows, since neither sign restrains the other's spending and both regard generosity as a virtue.
The second friction is bluntness against pride. Sagittarius says the honest deflating thing without malice. Leo, which does not lose an insult, treats it as a public diminishment, and fixed fire does not forget a public diminishment quickly.
Why two fire suns settle nothing
A shared element indicates temperature, not fit. An enormous number of people carry a fire sun, and this pairing occurs across every kind of outcome.
The useful comparison is the Moon in each chart, which decides what each of them needs when the performance stops, followed by Venus and Mars. If either chart carries strong earth or water, the pairing usually gains the caution and the emotional attention that neither sun supplies. That is a question about two charts, not two birthdays.
Questions people ask about this
Is Leo and Sagittarius an easy pairing?
Socially, generally yes. The difficulty is constancy rather than warmth, and it comes from the difference between fixed and mutable fire.
Why does Leo feel neglected by Sagittarius?
Sagittarius gives attention to everyone present. Leo, ruled by the Sun, reads a distributed attention as a withdrawn one.
What does this pairing lack?
Earth and water. Practical arrangements slip, and neither partner reliably notices unspoken hurt in the other.
Do we need the full charts?
Yes. Two fire suns describe a tendency in a very large population. The Moon, Venus and Mars describe these two.