I've worked in Canadian Federal sector after decade+ in commercial sector. My mind was blown - they do not compare:

1. Speed is an order (or three) of magnitude lower.
On anything - from macro-scale items such as signing a contract, designing the solution, creating the plan; to micro-scale items such as opening a port (2weeks-2months), creating a VMWare VM (2weeks-2years), obtaining a standardized laptop for new team members (2-weeks-3months).
(Yes - you read that right - there is a set of two well defined VMWare windows VMs we have literally been waiting on for two years)

1b. After my first project, I reviewed the openly available "lessons learned" from variety of Gov't IT projects, and in the top three, uniformly, you'll find a sentence like "External vendor did not have sufficient appreciation for nature, complexity and speed of government processes". Truer words never said.
We became faster when we slowed down to the oragnizational level: if we tried to do something in 2 days that government does in 2 weeks, it'd take us 4 weeks of hitting our head against the wall and causing havoc. Once we understood the 2 weeks it takes and built it into our plans, then 2 weeks it took.

3. As a citizen, I think of "The Government" - a single, big, overarching entity. Forget about it - it's really a lose and overly-formalized set of practically-independent organizations. IT integration of Department of Agriculture to Ministry of Labour is like integrating Walmart to Tesla. Different standards, processes, networks, firewalls, etc. It can take couple of years to agree and consume standardaized webservices across departments

4. Like many large organizations with variety of responsibilities and products, stability and predictability are much, much more important than speed. They need a solution that will last 20 years and a vendor that will exist and support it for that long. They can't change frameworks across 42 datacentres and 300,000 employees every 2 months. When their budget works at best on yearly basis, they cannot change their CIO roadplans quarterly.

5. This is a personal revelation and people may disagree: we want, or rather demand government to be that way.
Due to requirement on transparency, fairness, documentation, we the public end up pushing government in the corner. They cannot just pick the easy right choice in two weeks - that'd be in the Globe & Mail (think Washington Post;) as unfair process, favouritism, lack of transparency... other companies would outright sue. So you get a two year procurement process that ultimately WE demand.
Same for every decision at every level - it must be examined, discussed, commented, documented, covered. Everything has to be supported at an order of magnitude higher level than in commercial world (and note it has to be a well-supported, not necessarily right decision).
Government procurement and processes have documentation and checkpoints which in some ways can be wonderfully stable and structured, in other ways immensely frustrating.

My mentor told me early on: think of everything you do in the context of front page headline: "Consultant does X on public money"
So I can't buy lunch to my colleague I've worked with for years ("Vendor tries to bribe public servants"), cannot have a kick-off dinner for the project ("Consultants eat and cavort on tax-payers' money!!!"), etc.

My personal fear/nightmare is how I'll integrate back into the market having adapted to the public sector way and speed of doing things. Reading about neck-breaking speed of JavaScript frameworks and public cloud changes out there "in the real world", doesn't help my sense of peace :P :P :P