Celtic - Many reasons, they think we are the only club with a problem (sectarianism) well just because they dealt with the problem earlier this makes them a perfect club. Its not as if they have ever been perfect, I dont know to my knowledge any paedophiles that ever helped in running Rangers Boys club.
Agree slightly with El Diego to the fact Celtic think they are a much bigger club that they are. Both teams in Scotland have a bigger fan base than most of the teams in the Prem, have more of a tradition but we still play catch up. The Old Firm will always be big fish in little ponds whilst they both play in the SPL. We can never command the same tv fees so we can never compete to buy the same players. The difference in ambition shows the level or size of Scottish clubs compared to English, Celtic like us were happy to get the last 16 well Man U, Chelsea and Liverpool are happy when they win the tournament. This is not going to happen in the near future for a Scottish team, not since the early 90's when Rangers where so close to reaching the final.
The fact Celtic have the ability to take 200,000+ fans to Seville doenst make them the biggest club in the world, it shows the fact that they have a great support from two countries and one of which is a two team counrty.