with Taurus
There's a natural, high-strung 180 degree angle between these signs.

Unlike Taurus, Scorpio has much less personal barrier and is more willing to share. Unfortunately, it is unable to comprehend the idea of personality barriers and as such often tramples over Taurus red lines. Scorpio is less pent-up on material things than Taurus is, and has a tendency to mishandle these things and is often careless in acquiring proper Taurean permission, which is a common flashing point.

with Sagittarius
These signs are adjacent to each other.

Although this association can be quite exciting, at least in the beginning, Sagittarius tends to be too footloose for Scorpio, which may well be of concern to the more clingy Scorpio. Scorpio does not like to feel as if its close associations may disappear in a moment's notice, as it invests a lot of emotion in its bonds with people. On the other hand Sagittarius tends to be more impulsive and adventurous, and may elect to embark on a new expedition without much of a proper notice.

As a result, this association may be quite worrisome to Scorpio, and often somewhat suffocating for Sagittarius, which may become resentful of this. However, the longer it holds up, the less likely it is for Scorpio to give it up.

with Leo
Basic idea - exciting but strained

There's a natural, frictional 90 degree angle between these signs.

This association can be quite exciting and fun for these signs, at least at the beginning, and they may well share some ambitions together. Difficulties often rise from Leo being more open and socially active, which can make Scorpio somewhat anxious and perhaps jealous of attention Leo may give to others. The demanding nature and "heaviness" of this association may frustrate easygoing Leo and make him break with his loyalties. Such an occurrence may well exacerbate the situation, however the longer this relationship has been holding up, the less likely it is that Scorpio will give it up. Both signs can be stubborn in their ways, and may clash on this basis as well.