Tradition lends itself to mindlessness, stagnation, and strife far more than it lends itself to anything worthwhile. It might bequeath happiness, which is fine if it is not happiness coming maliciously at the benefit of others, but if it the tradition is conformist (e.g. Christmas) or mindless (the invasion of the Ottoman Empire to free already mostly free Christians), then this happiness is not worthwhile at all, whether or not the happy person realizes it (think of 'ignorance is bliss' and all).
The first and most incredibly dumb indulgence of tradition is to follow tradition with no thought for what or why one is following along. The gravest and easiest way to demonstrate this occurring is the repugnant manner in which holidays are celebrated, but it easily may occur in other places, such as how we speak or espouse morality or think of emotions (which is of course very much so influenced by this inherited and ignorant tradition of morality).
The reasons that the celebration of holidays is repugnant are multifaceted. The first is that the occasions to celebrate a holiday are fixed by tradition, often incorrectly. Christmas is correctly a day to celebrate a pagan god bull with a giant dick instead of Jesus. Thanksgiving is a day that ignorantly espouses unity and thanks ignoring the joke that the holiday is due to our massacring of the Native Americans. Furthermore, it is not even sensible, since people are not on the whole grateful at all, so they are getting together and lying to themselves and the world (at least more than usual)! An aside: the tradition of celebrating 0 AD, setting dates by Jesus supposed birth, is ALSO incorrect (which is why common era, C.E., and before common era, B.C.E., are commonly used now). Jesus was born at some point between 4-7 B.C.E. if the Bible is true at all, but if you want to mistrust the very book that you believe in, then you can certainly follow in the tradition of not understanding the religion you espouse as utter reality.
Granted, this is not necessarily a condemnation of tradition, but people in general when I detail the other largest reasons, which are that people need to force a day to be especially happy or celebrate some cheerful matter and the centering of these holidays around food and alcohol, which lies contrary to the sense that there is some greater humanity reflected by these holidays; they are ignoble instead of noble. Is it bad for people to eat or drink? No! It is bad that all this mixture of tradition and human folly has centered around a NEED to force this to occur! So the conformists think such days actually are important; they are fools. Which leads to the point that those who are not mindless conformists are tyrannized by this most cruel culmination of events and the incessant 'throwing in their faces' of each and every popular one. Now, I will grant that these holidays do genuinely make some people blithely happy, but most people are only parroting a pretend happiness that comes from the excitement of people deciding to parrot something at the same time, which is a false excitement and will make them the worse for having experienced it. Any person who enjoys this excitement does so because his or her life and mind are mundane, dull, unused, and unfulfilled. The satisfaction that ought to be supplied by themselves is instead to be supplied by others and the tradition inherently vested in such glorious days!
You might think I have forgotten the consumerism aspect of this, which is the most prominent repugnance, but it is so transparently repugnant that I do not even care. A majority of people probably find it repugnant (but many go along with it because society dictates they must or they see something attractive), and any who do indulge heavily still probably realize how pitiful what they are doing is. This aspect hardly merits consideration.
That morality, for the most part, stems entirely from practices oppressive to the senses and to instinct is absurd. Any time that an action does not directly (or one could argue malignantly, but I think it does not matter if there is ill intent or not, you do not bother someone who is not asking to be bothered) cause someone injury, then it is not immoral. It is absolutely, emphatically proper. If one wants to fuck in the park at 3:00 A.M. with no one else around, then it is a great thing! To address sexuality in general, the tradition of it being scandalous and impure (outside of marriage, but to some no matter what) is so entirely offensive to rationality and sensuality as to be insane. Sure, there is a risk of pregnancy and STDs, but when both members of the relationship (or more than two, whatever!!) understand the risk before engaging in the action, then there is no justification for it being wrong if it does not then interfere in some other lives. I mean DIRECTLY affect; a mother or father being upset about their son or daughter fucking is NOT direct, it is indirect and an invasion of basic rights. The tradition of thinking men having any femininity or women masculinity wrong is blatantly wrong, and the very traditions of what is or is not feminine or masculine is very often blatantly wrong as well (although that is less morality, but people portray it as such incorrectly). To think that pride is a 'deadly sin' is an outrage. Pride fuels men to the zenith of their abilities, to act when they might otherwise not, sometimes to ruin, and sometimes to greater success than seemed feasible at all. Emotions have drawbacks when people utilize them incorrectly, they are not good or wrong by themselves.
Reliance on tradition to formulate any part of one's ideology is also insane and should easily be realized as ignorant, but, unfortunately, even for one who realizes this, tradition inexorably constrains one's life. The way banks go about their business (look at how that worked out in the last year) constrains our lives due to tradition. The absurd concept that waving a flag makes you patriotic is impossible to escape, and ought to rightfully make one angry, as, at least in the United States, our tradition of patriotism is nothing but destructive because it creates massive ignorance and an inflated sense of ability that is NO LONGER TRUE IN THE UNITED STATES - THE SUPERPOWER HAS FALLEN. Now, with the greatest of asseveration, let me say that tradition ought to guide us and lead us and teach us; knowledge can do nothing but help us, and many traditions are genuinely from knowledge, and so long as one examines and understands that knowledge at least passingly, then marvelous. The tradition of how to properly run will help oneself (but, for instance, it seems maybe not the traditions of squatting and leg pressing and et cetera are as valuable as used to be thought!). To allow tradition to entirely dictate the actions of our world would cause massive failure and destruction, and it is a shame that humanity takes decades or hundreds of years after a tradition is proven rubbish to abandon it (and I am using humanity to refer to a majority, surely it is impossible to eradicate all but the most supremely and impossible to refute traditions in entirety; the rest will always have someone to espouse them.)
EDIT: I am going to add this as maybe a way to clarify and paraphrase my entire viewpoint as pertains to holidays: the problem is not with people being happy or excited about something, the problem is where they say 'happy Christmas' as opposed to 'hey, so what fun activities did you do today? :)'. The former is an artificial and generic construct that does not impart any personal meaning, but the latter actually specifically addresses the person.