Learn English – the logical difference between “to seek” and “to look for”

I feel like the word pail almost always describes a metallic object, shaped in a near-cylindrical fashion. Sometimes a pail can be wooden, but rarely. Buckets can be made of any old material, especially plastic, and can be shaped more strangely than pails.

In addition, bucket has some interesting and amusing uses in slang:

1. In its plural form, it can be an expression of unalloyed happiness. It comes from the slang term from having just scored a field goal in basketball. For example, if you had just won something unexpected in the mail, you might say "Buckets!" to celebrate it, just as you might having scored playing basketball.
   

2. It can describe a particularly decrepit vehicle, a hoop-ti; most often applied to vans.

3. It's an urban slang term for urban-style hats, typically wide-brim and loose fitting.

4. It's an urban slang term for expensive rims on a car. As so memorably used by the rapper Yung Joc, "...ride around slow so you can see the buckets on my feet [tires]..."
   

Pail, sad to say, is utterly lacking in this regard.

EDIT: Taking a look through Google's N-Gram viewer, it's not hard to see why:

This comparison of bucket and pail from 1800 till today shows the latter's usage diverging noticeably from the former's around the era of 1940–1960, to becoming a much less popular a synonym for the former nowadays. The chart makes a lot of sense to me, at least superficially; the 1950s–1960s was an era where college attendance and job mobility were first greatly expanded and democratized, and where a lot of young adults who might have grown up to work on the family farm in older times instead found white-collar, professional work. As pail in literature is strongly associated in my mind with farming contexts, it makes sense to me that authors would have limited their use of pail in that era given its more limited relevance towards their target audience. If a word doesn't quite have a "regular" currency, obviously there will be fewer opportunities for it to make its way into slang usage.

Putting aside the different grammatical constraints mentioned by @Gaston Ümlaut, there are constructions where either preposition can be used but the meaning usually differs...

...where in most cases a "call to action" is addressed to either the population at large, or everyone within some substantial community, but a "call for action" is normally addressed to government, or the leaders of some organisation (note that "a call to arms", which is far more common than either of these, is also invariably addressed to large numbers of people, not to leaders).

In most cases, a "call to action" actually seeks to persuade large numbers of people to do something "intermediate", which will put pressure on leaders to carry out the desired "action" (everyone should write to their government representative, so the government will change some policy, for example). It's fairly unusual to see the expression "call to action" used in contexts where people at large are being asked to do something that directly resolves some problem (turning down house thermostats to combat global warming, for example).

Effectively, a "call to action" asks everyone to agree action should be taken, but a "call for action" asks the relevant people to actually do it.