Not the view of all City fans. Maybe that's the generation gap showing in modern football. Celtic appear to have a much younger match-attending fan base in general (compared to other clubs), as in teens-30s which I imagine is what generates that "special European atmosphere" that the older fans don't have to start. Whereas, at City, I look around at the ground and it is overwhelmingly middle-aged - there are few pockets such as "Kippax Corner" and the South stand where younger fans congregate (coincidently where all our crowd's singing comes from at the Etihad). The north stand (allocated Family Stand - such a bad idea for atmosphere) has the families and therefore, generally the younger kids. Hopefully that doesn't sound "ageist" as obviously older fans were the football culture when singing was at it's peak, when they were younger. They've seen the game change and don't like it/have become a bit bitter about it.
Any multi-millionaire jibes at footballers from fans, media, politicians is just lazy and I'm sick of hearing it - Football is a huge business, therefore, huge sums of money are involved and the assets benefit where the demand is there for 'em. Common sense really, that's capitalism. It's not even relevant to atmosphere.
As for our atmosphere - lots of our fans outright avoid going to CL games because of a strong dislike for EUFA and the competition itself. It's gotten better since last season but before we were regularly frustrated with referring decisions that appeared bent in favour of the likes of Barca (our naivety to European refs played a part too which we've gotten over) and things like making CSKA Moscow away non-attendance because of CSKA's racism whilst loads of CSKA fans got tickets through EUFA/sponsors - effectively punishing City fans (this is why we started booing the anthem, besides them being found bent and FFP which was clearly to hamper us and pushed by the likes of David Gill, rag director with his fingers in the pie of FA and FIFA).
What other fans don't think about is that we've gone from league and a few cup games a year to being successful in 4 competitions in terms of how far we get on a season by season basis. If your also a regular away traveller that's a hell of a lot of expenditure for the fan whilst we've also got a bunch of corporates that've been brought in to "monetise" the fanbase under the pressure of FFP. That is why the odd cup game might have a lot more empty seats than there should be. I think there is some kind of problem with sponsorships getting tickets that aren't going to fans that would attend too, as even during the sell-outs (which is regular FYI, since other fans never seem to look up the facts) - I always see the same clusters of empty seats in the family stand especially (from where I'm sat) - these are what are easy to see on TV. Yes we have the lowest season ticket in the league but that was a marketing initiative for the expanded stand (it's just the highest seats) - I've witnessed many, many of our long-term fans being priced out over the last few years, who can only afford the odd game now. The atmosphere has plummeted during this time; we were still laughing at the rags for having a library in 2012 and I felt the tide changing after that as tourists/casuals starting to replace those priced out. Then, there is also the aspect of success where we expect to win which we're not used to long-term like Celtic, rags etc. Celtic has the nice balance for atmosphere/character of pulverising their league and then being underdogs in Europe; when we play shit, it's generally because the players are being lazy or not putting sufficient effort in for the fans - probably where the multi-millionaire thing that people bring up comes from because the likes of Nasri would play shit then you'd see pics of his flashy Ferrari and house. That's the difference in our clubs between the fans getting behind the players or not - ours have the quality to wipe the floor with the other team but sometimes seemingly couldn't be arsed (especially Yaya) - this was the problem with Pellegrini's last two years and the year Mancini got the sack.
Traditionally, we have a strong, solid fanbase heavily from Manchester but also have traditional supporter bases in other places like Sweden, Sierra Leone that have followed us a long time/have Manc links. The difference with Celtic is, you have one of the biggest supports across the British isles because of what you are. Your not so much as a club with a global fanbase, your non-Glaswegian fans are probably overwhelmingly Brits/Irish with a shared culture (such as singing at football), not visiting tourists like rags for example (or us for CL games). That's your advantage over every other club in the UK.