I'd like to echo jsalvatier's first point, and add one plea in "favor" of intolerance. Namely, tolerate your intolerance.

What this means in practice is roughly, instead of thinking "I'm acting/feeling intolerant - I'm a bad person," try "I'm acting/feeling intolerant - let me note the context, and the results so far. Let me think about what to do next." Try some of the alternative, more-tolerant responses suggested by LWers, and note their results too.

Keep separate in your mind your thoughts versus emotions versus behavior. You can have intolerant thoughts and tolerant behavior, which might (or might not) give you all the benefits you seek from tolerance. Emotions are sort of a middle ground, since they tend to be harder to keep private, but are often less salient to others than your behavior.