I think it's mainly due to the form and lenght of the historic process for the formation of those entities. Let's take a closer look a the different states.
Switzerland:
- The most stable of the mentionned states is also the one that started forming earliest (1291 with the "union" of the first 3 cantons).
- The Swiss Confederancy may have started forming for multiple reasons like trade, but it was its military side that made it grow and in time allowed the Confederation to become de facto independent from the HRE.
- The ethnic composition of the Confederation was from the start rather homogenous.
- Geography also plays a role: distances between cantons are rather short albeit sometimes aggravated by the mountainous terrain, but is also this terrain that isolates the whole of the coutry from its neighbours, which i think is also a factor playing in favor for its unity.
Very ancient union of very similar people with common goals (and enemies to protect from) in a sort of Alpine microcosm.
The United Kingdom:
- The process of unification in the British Isles begins also quite early (with Wales and English conquests in Scotland and Ireland) but its also more of a back and forth culminating in pesonal unions culminating in political unions between different nations in the 18th and 19th centuries (this is an extreme oversimplification).
- National identities in the British Isles were and remain rather strong (Irish, Scots, English, Welsh?)
- Geography cuts both ways here as the insular nature may favour the integration of its inhabitants in a single state, but also means that different islands push for different states.
Overall the UK is a more complex and very particular case. Here the it was mentionned as one of the successful states, but its previous iteration (The United Kingdom of Great Britain and Ireland) may be considered as failed or half failed seeing as Ireland became independent. This again I think relates with how the union(s) came to be in the first place and the balance of power between its different components. Starting with English domination, then giving more and more autonomy to the different nations in order to avoid their separation, this ultimately failed with Ireland and has worked with Scotland for now (but who knows for how long).
Yougoslavia:
- Came to be in the XXth century, by merging territories that until (more or less) recently had been under the rule of big multy ethnic empires (Austria-hungary and the Ottoman Empire) with the kingdom of Serbia, sometimes by simple annexation.
- While the idea behind Yougoslavia was that of an ethnic state for Slavic peoples, it was very very diverse with nationalisms, different religions and historic backgrounds.
- Mountainous geography of the Balkans wouldn't help to the integration.
The main reason I think the Yougoslavian experiment didn't work was it's enourmous diversity. It survived while the central authority (the King, Tito) was strong enough, but then it busted in the worst possible way.
Cran Colombia:
- Was formed in 1820's (1819-1822) as part as the process of Latin America Independence and lasted until 1830. It was formed by the territories and peoples that use to form the Spanish Vice-royalty of New Granada, keeping the same capital: Bogota.
- The ethnic composition of this state was rather diverse (see the "casta" system in the Spanish Americas), but it didn't break along those lines but rather along more "nationalistic" ones.
- Very large territory with mountainous terrain and lots of dense rainforest. The vastnes of this territory actually is IMO at the roots of the causes of failure.
The terrietories forming Gran Colombia had a fairly similar experience of Spanish rule for 500 years, but they did so in almost complete autonomy and isolation from the others. In theory Panama, Caracas and Quito where under Bogota's authority but in practice, the distances made that almost all the time they where left alone and developped their own criollo and mestizo elites, that would later call for independence from Spain.
When Gran Colombia was formed there where 2 main currents at odds: Centralists, led by Bolivar, that also called for a stong president with a lot of power, and Federalists, led by Santander, that viewed the centralism as similar to the monarchy, and called for more regional power for the former colonies. In the end Bolivar prevailed and the local elites rejected the idea of being governed from Bogota and broke away.
As you can very obviously see i'm not an expert in the history any of these regions so feel free to refute, correct, add to anything in here.